Ember hurt herself

Worried about Ember, my service dog. This past weekend when we went to our friend's house, Ember and my friend's service dog were playing in the yard and roughing around, and Ember ended up running into the chain link fence, catching her foot on one side. There were no cuts or obvious damage, though it was tender and a bit red when it first happened. She's been limping on it and favoring it since. We haven't really gone anywhere or done anything since Saturday when it happened, trying to give her time to rest. I tried wrapping it but that didn't make any difference.

She's still limping. As a mobility assist service dog, I rely on her being able-bodied when I have bad days and need her to help steady / brace me when I get sore, fatigued, or suddenly dizzy. We had to delay going to the post office and grocery shopping because the lines were so long and store so crowded, and I didn't want to force her to try and exert herself for such a long period of time.  I'm hoping it is just a sprain or something and just tender. She doesn't cry out or wince a lot when the area is manipulated, and there is no swelling or heat / inflammation at the spot.

I'm just dreading if it doesn't get better within the next few days because I'll have to make a trip to the vet to get x-rays to see what's wrong. I was still paying off Wasabi's vet bill, so I am sure the vet will want more of that before they treat Ember. Cost of x-rays will probably be $200+ for that view/area.  So I might be forced to use some of the money that was supposed to be used for my oral surgery for paying for the vet bill instead. But I don't want my poor dog baby to be in pain. I need her to be well again so she can continue doing her job helping me.