I have a mole on my arm which is raised and about 3mm big. i have noticed 3 tiny white patches in it is this bad?

Sign: Color variegation in a mole is not a good sign, in general. I would recommend that you have this mole evaluated by a dermatologist very soon.

Needs to be checked: Most raised moles are benign. Most early melanomas are falt. But change in colour always needs to be followed closely. Go see a dermatologist, they may advise a biopsy if there is sufficient concern on his/her part.