I'm a 21 year boy.weight is 82kg and height 173cm.now I am getting metformin 500 slow release tablet every night.is that good?

Good, how so ?
Please clarify your question..

I'm getting this tablet for weight loss.but I'm not a dibetic patient.so is there any problem in this?(side efffect etc.And I'm sweatin too much(specially face) even morning.And I have lot of pimples in the face.(face is oily)what can I do for this?

Unless you have been prescribed this medication then you should NOT be taking it as it lowers you blood sugar.