Melanoma ? Skin Cancer ? Mole ? Nothing ?

i am 16 years old and i just picked a hole under my breast with a needle and something came out . it was kind of like puss but it was more cream colored and i squeezed it like a pimple and something else came out . it looked kind of like skin tissue but it was cream colored also . then i whipped the hole with a tissue and peroxide and nothing else came . i have eczema and keratosis pilaris and a mole that is strange looking on my butt . its discolored and i scratched it and it's like a light spot like if a scab had healed on the top of it now . my mom just got her job back and got her insurance back and she wants to take me to the dr's and i am really hoping that is it is not melanoma . i have googled pictures of it but my mole doesn't look like that . do you have any idea's or anything that can tell me what is going on ? or should i just go to my pediatrician ? PLEASE TELL ME NOW !!!! :'(