My cuton pressure is 42 and my tank pressure is at 39. My cutoff is at 68. Is this okay or can it cause damage from being too high?

40 and 60 are pretty typical. 68 is a little on the high side and makes your pump work harder than is necessary. I'd back up the cut out to 60 if it was me.

As for the tank, most tanks are rated to around 100 psi. You might want to double check your tank's rating but I doubt that will be an issue for you.