Sorry to hear about your bad nail clipping experience. Hope your dog is feeling better soon.
I would try to keep him off payment and other rough surfaces for a few day. This will allow his nails to heal over the quick (the sensitive exposed nerve endings). Abrasive surfaces can reopen the healing quick before the nail has a chance to grow over it.
Keep some steptic powder handy in case your dog's nails bleed while they are healing.
As for the pain, I don't know of anything to put on them.
The only long term effects might be that he will be skiddish when it comes to having his nails trimmed, so you may have to take it slow and work with him to over come any residual fear.
Cutting a quick can happen once in a while, especially if your dog has dark nails. My dog has some light and dark nails. So when I clip my dog's nails the light ones are really easy to cut, where as the dark ones can be a little nerve racking for me.
But if you are having a professional groomer do the clipping and she cuts into the quick on every nail that's just unacceptable. Definitely time to find a new groomer.
