Does the skin coloring change appear in more than one location?

Dermatologist, or skin doctor, is the one who can give you an answer to any question considering your skin.
Melanin, or, skin pigment, and its production and distribution, can be affected by many factors, among which is sun radiation and heat.
Changes in any of these factors can increase or decrease pigment production.
Your skin change is known as post inflammatory hypopigmentation, and, usually, follows healing of certain inflammatory disorders (ex. dermatitis), burns, and skin infections.
The white appearance is related to scars and atrophic skin, and, spontaneous repigmentation may some times occur.
Generally, the skin pigment changes don't cause any major problem to health, but, is good to know that this part of the skin can be more vulnerable to sun exposure, thus leading to greater changes for cancerous appearance.