I'm sorry that this happening. First off, as everyone else said - I think you should find yourself a new therapist. I know that can be hard and scary to do. But you need someone who is trained in CBT (cognitive behavior therapy) and hopefully trained in doing ERP (exposure response prevention). This is scientifically proven one of the most effective ways to treat OCD symptoms long-term. If your therapist doesn't understand your symptoms, then I would question her ability to effectively treat your diagnosis. I hope that you can talk to him/her and that he/she might be able to help you with a referral.

Second - have you spoken with your GP about this? You mentioned problems with cysts. I know that you know that your fears are irrational, but OCD is not rational. I know that your GP is not necessarily trained in treating OCD but it would give him/her an explanation.

Lastly, I understand completely the pain and the fear you are experiencing and I urge you to seek further help. Please do not overmedicate with over-the-counter drugs. Long term, that can really damage your internal system. It might not seem like it right now but you will get through this.