Based on your description, the raised scar on your chin could be either a keloid scar or a hypertrophic scar. It may be best to consult a doctor so that he/she can have a look.
Keloid scars/ Hypertrophic scars can be treated with steroid injections. This helps to flatten the scar. Depending on the size and thickness of the scar, a few sessions may be required.
Hope this helps!
