Hello,
Is there any history of injury or hurt to the area? Any underlying medical condition?
Medication:
Meantime, take homoeopathic medicines - Arnica 200 and Rhus Tox. 200 - take both of them thrice daily for 1 week. Also, apply Schwabe's Topi-Arnica and Topi MP Gel on the affected area in circular motions gently thrice a day. And wrap crepe bandage over it.
Get back to me thereafter.