Suggest Treatment For Bruise, Pain And Soreness On Buttocks After Fall

10 days ago, I fell while getting onto my sail boat...severely bruising my left buttock...there was pain and soreness that has reduced but is still present in certain sitting positions... the bruise is deep and beginning to change color to brown and yellow however I have noticed that there are 3 bumps underneath the bruise (don't think it is a hemotoma). While investigating possible causes on the internet, I came across reports of "denting" occuring at the site of the buttocks when there was an injury similar to mine. Is this likely and how can I prevent it?