from what i have read it is very severe and distressing to say the least. here are three things that i feel you can try and god willing you shall create your own miracle.
1. find a good hypnotherapist and ask them to do an age regression to find out why you are on a sub conscious plane you are rejecting your own skin and to help you make peace with it.
2. get a green aventurine crystal and an amethyst and make crystal charged water with them and wash your skin as many times as you can with that water. also drink the water, intially maybe 3 times a day and slowly build up to as much as you can have.
these two things worked on together should get you a near permanent solution to your problem.
3. and last but not the least stand in front of a mirror and genuinely love and accept yourself for who you are and what you are. (this is actually the most important step)
PS: it will take a bit of time so dont expect instant results