so I used scetch it learned leer I cant battle with it how can I get scetch back please help
Smeargle learns Sketch every ten levels, so you'll have to wait until levels 11, 21, 31, 41, 51, 61, 71, 81, and 91. Whichever yours will level up to first is the soonest you'll learn Sketch again.
Smeargle learns sketch numerous times, it does't get it just once. You can go to the move tutor if you are at level 100. From my memory it learns it ever 10 levels
Go to the move reminder in minstralton city, use her help to remind your smeargle the desired move in return of a heart scale!