Hi and welcome to YT
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I'd get this girl to the vet asap as she could possibly be in a LOT of pain here, especially with a tooth issue. Teeth issues can be excruciating - so if there is an issue, you absolutely must find a way to address it ASAP. It can't be ignored.
All skin issues are secondary to either allergies or some other disease state. What do you mean, exactly, by saying she has "skin issues" - please describe...? If she is starting to lose actual hair, then she should have her thyroid checked and Cushings should be ruled out.
Senior dogs can also pace/whine bc of age related confusion and dementia. In that case, meds can be helpful.