I was told that dandruff shampoo is effective in treating hypopigmentation (vitiligo) on my forehead. Is this true?
No. It can treat seborrheic dermatitis which can cause lighter color. Excimer laser, narrow band uvb, or microdermabrasion plus 5 floururacil can regiment vitiligo. See a dermatologist experienced in treating vitiligo.
No. Sorry but this is not correct.
Hairline. If it from vitiligo, it will not help. If it is flaky and whitish it may be seborrhea and then it may help.