There is only so much you can do with aftercare; a shallow, poorly done piece won't suddenly become amazing if you scrub it lots, nor is it likely that a very pale skinned person will develop huge keloid scarring, even from a deep well-cared-for wound.
When deciding on an aftercare routine, it is important to know the factors which will influence how your scar will heal, so you can choose methods that will exploit those factors and give the desired end result.
Factors which influence healing
There has been a large amount of research done in recent years to discover the optimal healing conditions for wounds. The faster a wound heals, the less scarring there will be. The focus of medical research has been the prevention of scarring, rather than the creation of scar tissue.
- A wound will heal twice as quickly in a moist environment, especially during the proliferative phase. However, a dry wound will form large scabs, which may create an uneven scar.
- a wound heals best in a slightly acidic environment. Aftercare products which create an alkaline environment will delay the wound healing process.
- a well oxygenated wound will heal faster than one that is deprived of oxygen. This is more related to the "drying" factor, which promotes scabbing.
- Foreign bodies
- Small foreign bodies (such as bacteria) are trapped by the cells of the immune system and are removed from the wound. Larger foreign bodies cannot be removed, so the body forms a pocket of scar tissue around the object.
- Repetitive trauma
- If additional trauma to the wound is suffered, the scarring will increase.
- Scars around joints and areas of high movement are generally the ones which form the largest scars.
There are other factors which affect healing of wounds, but these are ones we are unable to (safely) control, including diet and presence of infection.
When considering fresh wounds, it is important to keep the wound covered with a sterile bandage or dressing to minimize the risk of infection.
Possible aftercare methods
- Manual irritation
- essentially, scrubbing at it. A (clean) toothbrush can be used, or an abrasive substance such as salt or sugar mixed with Vaseline. The repetitive trauma will prolong the healing process.
- Chemical irritation
- substances like lemon juice and vinegar are often used to lower the pH of the wound.
- keeping the piece open to the air will allow it to dry out and slow the healing process.
- one of the most effective ways to promote raised scar formation is to pull the edges of the wound apart.
- BME QOD 
- Precision Body Arts Aftercare