A couple days ago me n this girl had sexs we used condom n all she give me head n all day ago I notice I have a lump on my part skin down below but its not on my **** when I touch it its get tender n it hurts... So today I went to go shower n I notice I have greenish yellow stain on my white boxers all I want to is it from the lump or do I have any type of disease n no my penis doesn't hurt when I go pee I'm just worry that's all

Probably an ingrown hair or a boil... put a hot compress on it a few times a day to bring out the infection and the root of the problem i.e. head or hair. If it starts to get really sore or red and angry looking you probably should seek medical attention.