Swollen Shaft Skin Issues?

Okay, so the first time my shaft skin swelled was after masturbation, the skin was soft and thickened enormously; after 2 or 3 days It went down. It happened later on and a third time, and now the swelling has not gone down for some weeks. When I retract my foreskin, quite a bit of skin bunches up at the base and halfway up the shaft. I'm concerned as to what to do.