I have A large bump just below the head of my penis. It was fine when I went to the restroom you know it was normal size. Then 15 minutes it was huge, it don't hurt and there is no pimples or colorish dots on it. It also shrunk from it's normal size to a smaller size than it was. I a virgin so I think that has nothing to do with the subject. So if you know what it is can you tell me

Get to an ER fast and try not to touch it. It could be something that could spread.
Does it have a whitish liquid inside it?

Whatever you do, DO NOT POP IT! If it is skin-to-skin transmitted, it could get bad.

Go 2 tha docter buddy

Yeah as a general rule, that's the one thing you have in life, take care of it.
Talk to your caregiver about this, it is nothing to be ashamed of.

My boyfriend had an ingrown hair which looked similar to what you are talking about. But because its close to the head... I doubt it. So... GO TO A DOCTOR!

Go To The Doctor!!

Once more get to the docs these are your family jewels you are talking about!