If you are hoping to somehow change the healing process so that a bruise does not appear dark and purplish, then unfortunately there is no way you can do this. Bruises are injuries in which capillaries in a particular area are damage by trauma, causing blood to seep into the surrounding tissue. These injuries go through a natural healing process in which they darken and then turn bluish and purplish over the course of three days to a week, or even more, depending on the severity of the bruises. This darkening and discoloration is more noticeable in people who have very light skin, but the discoloration is only temporary, and you should therefore not worry about it. The treatment that is typically advised for light bruises is known as RICE - rest, ice, compression, and elevation. Most people tend to skip the rest and elevation, but each element in this treatment technique is equally important. Elevation helps reduce swelling and also improves circulation, which in turn speeds up the healing process, while rest is essential so that the damaged tissues get a chance to repair themselves without constant strain. If you properly use the RICE treatment, your bruises will heal quite rapidly. Of course, for more severe bruises it is always important to get medical attention. Severe bruises can be accompanied by more serious internal damage and long term consequences, and are therefore best treated by a medical professional.
If you are referring to the dark scars that are sometimes left after a bruise has healed, then there are indeed things that you can do to tackle this problem. It is of course impossible to entirely avoid scarring, but if you treat an injury well, you can minimize the severity of your scars. Most people will advise you to avoid peeling the scab once it has formed, and you should indeed do so. However, contrary to traditional advice, you should not keep the area dry - keeping the bruise moist with an antiseptic ointment is much more effective at preventing scarring. This is partly because this prevents infection of the wound, which apart from the obvious complications also worsens scars. In addition however, keeping the area moist helps the tissue to grow properly instead of developing unevenly, with either a lump or a crater, as is so often the case. Hygiene is of course very important - wash your bruises gently every day, and then reapply the antiseptic ointment.
answered by G R