What Does A Puss Filled Bump On Upper Lip Indicate?

Hi, I have some sort of bump on my upper lip and I can't tell if it's a pimple or a cold sore. It has the resemblance of a white head with the white pus-filled middle but I've been putting acne cream on it the white part came off while rubbing my face dry with a towel. The bump seems to be bigger now however and the middle part which was initially white has come back and is now sort of yellow in color. It's quite annoying and I hate knowing it's on my face is there anything I can do to quickly get rid of this? Thanks