I forgot to mention the lump is very hard
The blood under the skin which causes the discoloration of bruising should be totally reabsorbed by the body in three weeks or less.
In your case,as the symptoms are persisting for more than 1 month,so it may be due to formation of hematoma because of blood trapped in tissues.This blood may need to be drained.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.