Our Staff

Dr. John Vassallo MD

Internal Medicine Physician

Dr. John Vassallo is a Board Certified internal medicine physician who lives in Howell, provided care and has provided care to Livingston County since 2005. As an internist, Dr. Vassallo treats a range of patient conditions from the common cold to complex chronic medical issues such as diabetes and heart disease. He is committed to working with patients to prevent the occurrence of chronic disease and take steps that lead to a long, satisfying life. This is achieved through communication, education, screening exams, and expert medical knowledge. 
 
Dr. Vassallo enjoys reading (history), everything outdoors, and rugby. 


What people are saying...

"Dr. Vassallo is AMAZING!!! If you want an honest and forthright doctor, he is your guy!"

"Dr. Vasallo is an awesome MD. He is very knowledgeable. He gives me the feeling that he really cares about his patients."

Payton Hirschenberger PA

Physician Assistant

Payton graduated with honors from Central Michigan University's Physician Assistant program in 2022. During his time at CMU, he excelled academically and demonstrated a passion for medicine. Following graduation, he joined Corewell Health in Grand Rapids, where he quickly established himself as a skilled and compassionate provider.

During his tenure at Corewell Health, Payton consistently provided high-quality care to his patients, earning an impressive 4.9 out of 5-star patient satisfaction rating. His dedication to his patients, combined with his strong clinical skills, makes him a valuable addition to our team.

Payton is eager to get to know you and looks forward to providing you with the same level of personalized care that you have come to expect from our practice. He is committed to building strong relationships with his patients and working collaboratively to achieve your health goals.

 

Camryn Ozuch, PA-C

Physician Assistant

Camryn Ozuch is a board-certified Physician Assistant who graduated from Eastern Michigan University's physician assistant program. She completed her undergraduate degree at Michigan State University, where she studied exercise science. During her time at EMU, Camryn became a member of the Michigan and National Physician Assistant associations, volunteered at local Ronald McDonald Homes, and obtained over 5,000 clinical hours of experience.

Upon graduating from Eastern Michigan University, Camryn began her experience in urgent care medicine, where she developed a well-rounded skill set and a calm, compassionate approach to patient care.

In her free time, Camryn enjoys spending time with her family, playing pickleball, and reading.

Camryn is committed to delivering high-quality, personalized care and looks forward to supporting you on your health journey. She is passionate about creating meaningful connections with her patients and strongly believes in collaborative, patient-led medical decision-making.

Terra Lynn, PA-C

Physician Assistant

Terra is a dedicated and compassionate Physician Assistant with a diverse background in both psychiatric and urgent care medicine. She earned her Bachelor of Science in Genomics and Molecular Genetics from Michigan State University before pursuing her Master of Science in Physician Assistant Studies at Lipscomb University, graduating in 2020.

With over six years of experience in psychiatric care, Terra has extensive experience treating patients with a wide range of mental health conditions, focusing on providing individualized, patient-centered care. In addition to her psychiatric background, she has worked in urgent care settings where she managed both acute and chronic medical conditions across diverse patient populations. Her broad clinical experience allows her to take a well-rounded and compassionate approach to patient care.

Recently returning to Michigan, Terra is excited to continue serving her community and building strong relationships with her patients. She is passionate about helping individuals improve both their physical and mental well-being through evidence-based care, education, and open communication.

Outside of work, Terra enjoys spending quality time with her family, being outdoors, and traveling.

Erin Gillespie, FNP-BC

Family Nurse Practioner

Erin Gillespie is a board-certified Family Nurse Practitioner who earned her Master's degree from the University of Michigan-Flint. She previously graduated with honors from Oakland University’s nursing program.

Throughout her nursing career, Erin has gained extensive experience caring for patients with complex neurological and neurosurgical conditions as a registered nurse at Michigan Medicine in Ann Arbor. Her clinical expertise includes caring for patients with stroke, epilepsy, traumatic brain injuries, neurodegenerative disorders, and other acute and chronic neurological conditions.

In her free time, Erin enjoys golfing, boating, playing with her chocolate lab, and traveling. 

Erin is dedicated to providing compassionate, patient-centered care and believes in building meaningful relationships with her patients. She is committed to empowering individuals to actively participate in their healthcare decisions and looks forward to partnering with patients to help them achieve their health and wellness goals. 

Sydney Krenz, FNP-C

Family Nurse Practioner

Sydney Krenz is a Family Nurse Practitioner dedicated to providing compassionate, patient-centered care. She earned her Bachelor of Science in Nursing from the University of Michigan–Flint in 2022. Following graduation, she began her nursing career in the intensive care unit, where she gained valuable experience caring for critically ill patients. Over the course of three years in the ICU, she developed strong clinical skills and a deep appreciation for evidence-based practice. 

Sydney is committed to building meaningful relationships with patients and their families. She believes that effective healthcare begins with listening, education, and collaboration. To further advance her nursing career, she pursued graduate studies at the University of Michigan–Flint. In 2026, she graduated with a Master of Science in Nursing and became a Family Nurse Practitioner. Her educational and professional experiences have prepared her to care for patients across their lifespan. Sydney is passionate about helping individuals prevent illness, manage chronic conditions, and achieve their health goals. She values empowering patients with the knowledge and resources needed to make informed healthcare decisions. 

Outside of work, Sydney enjoys spending time outdoors, reading, and with her family. Sydney looks forward to partnering with patients to improve their quality of life and support their long-term health and well-being.