Shaving isn't going to eliminate the shadow but it is still a better option than not shaving.How long have you had this problem and what does your doctor say? Do you expect the hair to grow back at some point or is it gone permanently? If it is unlikely to grow back, I would definitely look into the laser treatments. Your insurance may even cover the cost since it's due to a underlying medical condition.
As Razor said there is know way to get rid of the shadow , unless your hair turn white or gray.
Welcome, Lay! Are the patches all over your head, or in just one or two particular areas?
If I were in your situation, I would much rather be permanently bald than go through all those injections and the constant shedding and regrowing of hair. I'm guessing this is something that can't be cured -- and I'll further speculate that at some point the hair is going to stop growing back. I'd probably opt for the laser treatments but unlike most people, being bald has never bothered me. Think long and hard about it because once you travel down that road it cannot be undone.
I'm doing laser myself too, I'm 31 and was fed up with the significant shadow from significant MPD, and like you I dark hair and fairly pale skin.