Hello, I can understand your concern for bruise in right bicep. You have not guided us regarding your present age and sex with related medical history of taking any tablets so that I could have helped you better. Bruises are principally formed due to an injury or due to trauma to the small blood vessels of the skin. For the best part of the diagnosis I routinely go for platelet count and clotting time with bleeding time. These are easy tests of platelet function and coagulation factors done routinely in all the simple laboratories to rule out the exact cause of the problem. If these tests are normal then you can relieve your tensions regarding the bruise. The various colors are due to the internal change in the hemoglobin which is shoes yellow to blue to varied colors. You can take further guidance from a dermatologist. All the best.