I just thought I would give you some advice if your cat has been stung by a bee.
A few weeks ago one of my neighbours came to my door asking for help, her cat had been stung by a bee and the vet wanted big money to go out to the surgery to see her before any treatment, (this was a Sunday)
When I got to the cat, his foot was swollen more than twice the size, he was very agitated and stressed, the son had killed the bee and brought it down to show me, it was a bumble bee.
When a cat is in pain you have to be very careful how you handle it, because the lady couldn’t hold him properly (for fear of hurting him further) I asked the son, if I hold him could he have a look at the foot. So I scruffed him and held his back legs so he was supported but in the submissive position, like when his Mother would hold him as a young kitten, this makes them very submissive and they are usually quite calm.
As the son was looking so was I, we had a good look between the toes but could find no sting which is why we were looking, first and foremost for a bee sting you need to ensure the sting is not embedded still. There was no sting.
There was a slight reddening around the thumb so this we think was the site he was stung at.
So my advice was he needed anti histamine and ice pack on the swelling, but if she was worried or it got worse to get him to the vet.
I had to leave but promised to come back later, which I did. The lady had taken the cat to an out of hours clinic and seen a nurse who had a look and did the same as me, she then told her to go and buy some human antihistamine (not the non-drowsy) and give him a tablet every 7 hours for 24 hours and when I saw the cat he was very relaxed with his foot on an ice-pack and although the swelling was not gone he was much calmer.
He was out climbing as usual the next day, maybe lesson learned or maybe not, cats love things that move.
The main thing to do with a bee sting is to make sure the sting is out then ice-pack for the swelling but check with a vet to make sure. But be careful because some cats are allergic so always check with a vet.