My cat had 6 kittens the other day and I saw this when she was nursing her kittens. Can someone please tell me if this could be mastitis and what I can do.
It looks like an infection for sure, she needs an antibiotic. Call your vet, send them that picture and see if they will give you an over-the-counter antibiotic. You can find them sometimes online too. This is VERY painful for her. you might apply some human antibiotic salve in the meantime, make sure it does NOT have painkillers in it like some do nowadays. I feel so sorry for her. You could get some lickable treat to put the liquid antibiotic in, it helps with her accepting it.
Ouch! That may be fungal. You could try applying a feminine vaginal yeast creme such as Lotrimin or Nystatin may be prescribed by a vet.
Mastitis usually shows as red, swollen and inflamed mammaries and nipples. Mastitis definitely requires antibiotics. Either way, that is painful looking. You can email the photo to your vet, or she may need to be seen.