Wtf is this? And should I see a doctor or just let it be?
I wanted to upload another pic, kinda kooks like a vain
Just don't scratch it or pick at it and you'll be fine. Unless you're stacked you don't need to waste your money on a doctor.
Give it a few days/weeks, see if it gets worse, if it does go to the doctor.
You have an infection under the skin, like an infected pimple. Put toothpaste on it for the next week and see if it gets smaller and goes away on its own. If it doesnt, see a dermatologist.