What Causes A Lump And Soreness On The Half Circumcised Fore Skin?

hi im 19 years old and ive had circumsised when i was 11 or 12 but I don t think the doctor did a very good job. It seems that despite being cut, I still have a lot of foreskin leftover. Below the head of my penis, there s a good bunch of skin that I am actually able to pull over my pee hole without any pain or effort. Also, when I want to, I can almost cover my whole head with skin when I roll the skin upward. then theres a little yellowish like pimple appeared i dont remember when it is first appeard but i ignore it so now one day when ive wake up it feels itchy then i look at it its swelling red ,then theres a two hole leaking a pus in the front and back of the skin .how did it get like this and how can i cure it immediatly sorry for my grammar im not that good in english s