after kittens leave mommy cat

my cat had kittens 6 weeks ago and i just noticed odd shape large knotts around nipples, is this dried on milk and when will it leave? Shes been crying a little at first thought cause she missed kittens now dont know if she is in pain or not. She has an appointment Feb 25 to be fixed.

You let the kittens leave for their new homes?  Its early at 6 weeks.  Not catastrophal, it was common enough when I was a kid, but the normal minimum is 8 weeks,  if its no crash emergency.   Those who can, keep them at least 10 or ideally 12 weeks. 

  (one of the few exceptions are kittens from a ferale mom, where there are adoption homes waiting. Such kittens should leave earlier at 5-6 weeks).

The mom is of course missing her kittens, more so as they left earlier than she is biologically programmed for..

And yes, of course  the milk is pressing on her, causing some pains, maybe even inflammation.

You can try and massage them some, perhaps also have some olive oil of good quality on the tits.

You can probably have some human oil for sore tits.   I presume this oil isnt poisonous for cats - she will of course lick on it.   If in doubt, use just  olive oil.

Idea:  Home remedicum may also be youghurt... It is cooling if nothing else....       Use some plain unsweetened variation, preferably with lotsa of healthy bacteria in it.

Good luck!

This sound like she has mastitis. Which is a bacterial infection of the milk ducts. It's very painful. It needs antibiotic's from the vet to treat the infection also holding a warm compress on the teats can help soothe and provide some relief.