If you have to take the cat to the vet, don't decide to quickly pop to the shops on the way home. Parked cars, even if they are in the shade, can become excessively hot and in a very short time cats will suffer from heat stroke, and may even die. If your pet is stung near its mouth or in its throat the airway may swell and restrict breathing. Some animals may also be allergic to bee and wasp stings and quickly collapse. If you think your cat may have been stung in the mouth area, check that the airway is clear and take it to the vet's surgery immediately.
Bee stings are acid.
Remove the sting and bathe the area in bicarbonate of soda. Wasp stings are alkali, and the sting is not left in the skin. Bathe the area in vinegar. If your cat is one of those who likes to leap about in long grass, there is just a small chance that it could disturb a basking adder, with serious consequences. If you suspect that your cat may have been bitten by an adder, seek veterinary help immediately.