Between right thigh and penis shaft... was tiny and went away 2 months ago. Reappeared and has more than quadrupled in size? Am seeing a Dr tonight just want to see if anybody has any ideas before I go?

Also is painful to the touch

Could be an ingrown hair, a cyst, a pimple, an STD, and many other things.

There's really no way for anyone online to even guess, even if they've had something similar, that doesn't mean they had what you have.

The doctor is your only option.

Good luck, and don't worry until there's something to worry about.