Blister on cats paw? Infection?

Hi. I got home from work Sunday and my cat was limping. When checking her paw I see a blister like injury on her toe. I took her to the vet Monday and they really didn’t look at anything, because “it seems to bother her.” Very unhelpful lol. I sent them a photo and they gave me gabapentin and an antibacterial cream. I know it’s only been a  day but she’s still in pain and I feel like it’s looking worse. Does anyone know what this is? Should I soak her paw in salt water to help soothe it? Any advice is greatly appreciated! First pic was yesterday, below is today.

Hello and I'm sorry to hear about this complication with your cats' foot.  It does indeed sound painful; limping is a direct sign of pain (if you think about it, pain is the reason that a limping paw is not put to the ground) and given that the lesion is worsening despite initial treatment, I would advocate speaking to your vet immediately rather than waiting.  It could be an injury or burn.  It could be plasma-cell podermatitis, although it doesn't look like the single case I've knowingly seen - but I am concerned about progressive medical and systemic problems too, which can worsen with a0 time and b) trauma from a cats' tongue.  Your vet might ask to forward the picture to a lab pathologist for advice if they are unsure. Please will you let us know how you get on?