David,
Difficult to tell from your photos, but given that you have just had a big storm pass through, I would guess wind scorch. The leaves do not like strong winds, especially in those first few days after they open. If it is that, you should have some new leaves growing soon.
If it's not wind damage, I would try planting it out in the garden. A lot of plants prefer the more stable conditions of the ground compared to my (lack of) tender loving care of them in pots!
Good luck with it - you can never have too many acers. I have just succumbed to temptation and bought the gorgeous A. aconitifolium. Now I need to find somewhere to plant it!
