Chester Office : 908 - 879 - 8800. Hackettstown Office : ... Dr Geller’s Credentials; Xin (Cindy) Guan MD; Chester Office; Hackettstown Office; Testimonials; Gallery; Conditions. SKIN CANCER; Acne in NJ; Moles and Melanoma; ... compliant and available at no charge to patients. Patient participation in the web portal is optional, but we hope ....