Sorry to hear that you hit yourself so badly! It sounds to me that the bump you are feeling is most likely a bruise
or contusion under the skin. The fact that it is a purple bluish color with a bit of yellow is very consistent with this as well.
What normally happens when you hit yourself hard enough is that small blood vessels under the skin break and allow blood to leak out and pool under the skin. When this occurs, the new blood initially has a blue or purple color. However, subsequently the body will begin to break down and digest the blood, at which point the area will start to turn yellowish or brownish in color before disappearing gradually.
Since this sounds exactly like what is happening in your case, I think this is unlikely to be anything more serious than a bad bruise. Please schedule a visit with your primary care doctor
to confirm this. Your primary care doctor can also help you figure out if you should be taking any medication to help with the swelling or with the pain. I expect that you should start to be feeling better and notice the swelling going down in the next several days.