Caustic Touch

Your hand sweats profusely and becomes coated in a film of caustic slime. Make a melee spell attack against a creature you touch. On a hit, the target takes 1d8 acid damage. If the target was concentrating on a spell, it has disadvantage on its Constitution saving throw to maintain concentration. 

The spell's damage increases by 1d8 when you reach 5th level (2d8), 11th level (3d8) and 17th level (4d8).