Acne breakout during injectable VIT B12.

My son is 20 and underwent right hemicolectomy last year(May 2020) after which he was deficient on VIT B12 and currently takes VIT B12 injection monthly(he took them daily at beginning for week), Xtor-10, Aspirin 20, Neuro D from Neurologist. He is on this meds as after surgery he had minor stroke. However, it's been 5-6 months he is on this meds and having severe acne breakout. His dermatologist has prescribed Isotretinion(capsule) with other non medicated creams and serum like GAHA but the response is slow and also had applied Isotretnion cream and Adapalene cream but to no avail. Do you think it's because of the heavy meds he has been taking since two years(before surgery he was also on many meds like AKT and medicines for Gastroenterology) Waiting for your valuable response