When to the emergency room for a cut on my upper l...

When to the emergency room for a cut on my upper lip. They gave me one stitch and told me I didn't have to come back do to the stich will disolve by itself, and three weeks had passed and the cup is close but I have and fell a bump inside my lip. This probably means that they didn't use a disolveble stich, I Don't know what's to do now, I Don't want to feel this anconfortable bump in my lip.