I had a cyst under my foreskin which made the foreskin tight and sex painful. this week my foreskin has become very swollen (x3 normal). circumcision?

Don't wait. Go in: I would not wait to get this taken care of by your doctor. It sounds like you have an infection. Your doctor will need to determine the cause and treat it immediately. Your first priority would be to treat the immediate problem. The circumcision can be discussed, thereafter, with a urologist recommended by your primary care provider.

Urologist: You need to see a urologist for evaluation. Circumcision may be an option. Good luck!