Lump on my cats ankle

My cat came in 2 weeks ago (he is 12) limping on his back leg. I noticed a slight lump on the inside of his knee bone. We took him to the vets who gave him an xray and it detected just a grey area. He gave me pills and a syringe with something or other in it and told us to come back in a month. The lump has doubled in size but he isnt limpng anymore. Has anyone ever had this before? Thanks bigcat!

You need to ask questions then either ring or go back and ask him, especially if it's doubled in size. Write your questions down what you want answered such as:

A. What the pills and syringe are for?

B. What could the grey area be?

C. What's the next step?

Don't be scared to ask. Your paying the vet for a service and questions being answered is part of it.