Hello Anne,
Thank you for sharing your dream with us. Please take everything I say to the Holy Spirit for He Alone gives the interpretation.
There is someone in or will be in your responsibility that has a bruise from the past (swelling on the buttocks) and it’s your job to make them warmer (they’ve grown metaphorically cold). Basically, it sounds like you might have a healing role (could be love and/or social support) to play in this individual’s life.
Shalom!