Air bubble type thing on shaft for months painless, now it is red, getting larger, and painful. Please help. Image of what it is now.

(Image removed)

I don't open links. Chances are it's a cyst, which can grow around an ingrown hair or for other reasons. Go to a walk in clinic. If you are sexually active, of course also have STD testing.

It is a blister, just get yourself to a doctor and have it diagnosed properly. We can't diagnose on this site.

Your image has been removed. We have children who view this website. You will have to see your doctor for a proper diagnosis.