Under the knob of my penis there are little pimple looking things im not sure if it is a std or not ?
A pimple on the penis is not necessarily an STD, but you should get it checked if you have any reason to believe it might be. Some other possibilities include:
-An infected follicle
-An allergic reaction
-A fungal infection
-Just a pimple.
Most blemishes should heal up on their own, unless there is an underlying disease involved. You can speed up the process by keeping it clean, wearing breathable underwear, and applying a penis health crème (health professionals recommend Man1 Man Oil) with vitamin A.