Our dog seems to be having a little foot pain tonight. We will take her to the vet tomorrow but can we give her an asprin tonight to help her feel better tonight?

Yes. As I said at https://www.askmehelpdesk.com/dogs/dog-pain-81107.html

''No ointments that I know of. Never give a dog any of the modern pain remedies, Tylenol, Ibuprofen, etc. You can give it aspirin, 5 mg per pound of dog every 8 hours, a regular 325 mg tablet for a 65 pound dog. Buffered aspirin is better for the dog's stomach. For smaller dogs, baby aspirin comes in smaller doses.

I have heard that pain killer can allow the dog to aggravate the injury.''

Give her the correct dose and let her have a good nights rest. Be sure to tell the vet about it.