Hi. Pain in abdomen with a yellow bruise is suggestive of a few things. First is the possibility that you have done too much hot fomentation thereby the skin color is changed. There is another possibility of an abscess of the underlying tissues , may be subcutaneous or deep in the muscles or may be deep within like appendicitis, or colonic pathology like diverticulitis , tuberculosis or Cron s/ Get a clinical evaluation by a Surgeon and investigations accordingly to find out the cause and get treated accordingly.