From your picture, it appears that there are 3 components to your scar - it is hypopigmented, widened and hyperthrophic, as well as being depressed in some parts.
Treatment would depend on your requirements and how long ago the pilonidal excision surgery was performed. The definitive treatment of this is a scar revision with a Z-plasty and possibly a small Lindberg flap to correct the depressed components. This would be partially covered by Medisave.
Best Regards,
Dr Samuel Ho