I shaved down under 5 years ago for the first time.
Developed razor bumps and itching.
I used dettol to clean. The skin became kind of
Black/purple in between the thigh areas
Is there's anyway to get my skin back to my normal color

People who have dark hair tend to get discoloration from shaving or ingrown hairs. Some people prefer waxing because it pulls the hair out from the roots and doesn't cause visible discoloration or ingrown hairs. Using an alpha hydroxy cream or skin lightening agent may help fade the discoloration.

Thanks for the tip, I have dark hair and don't shave that often, but will bear this in mind, because I would not want my thigh skin to change colour or get any complications there because of shaving.

Hello there

Try mixing equal amount of Apple-vinegar + rose water. Use mix to spray dark area twice a day. You'll see result within 3 weeks time