does the potions use a move and i trained to 7 which is the max i think or is there more ways for me to get it up?
You can drink potions BEFORE going into a battle to buff them beyond your current level. I got stuck at the same point because I didn't know that. I was only using them mid-battle to replenish. If your skill is at 7, I think the medium potions can be drank twice to buff it to 8.4. Do that and use super effective skills and you should be able to defeat him.