Swollen leg?

[slawsonx]

I have attached a photo bare with how small he/she is but her leg is a bit swollen?
I do not understand what could be the cause of this or the most likely cause
Now last week he was out for a few hours a day as it got really hot and I do think this is linked to this problem
He is eating fine, drinking fine and getting rid of waste fine
He is walking on a little limp with putting little pressure on the foot compared to the other but a member of my family reckons it wasn't as bad as it was yesterday.
Anyone reckon what's the likely cause of this ?
I'm going to give it a few days to see the vet as apparently there has been improvement

 

[Markw84]

Very possible that it is some type of ant or spider bite, or bee sting. Since the other leg looks fine, see if it continues to improve.

 

[MPRC]

Check above the swelling on the leg to make sure there isn't something caught around it like a string or hair.

 

[slawsonx]

I've checked everywhere, nothing to cut off any circulation. I do think maybe a ant or something and now I'm paranoid about any infections. We will see

 

[slawsonx]

Update: still has a limp but the swelling has gone down, it's not on his upper leg but his ankle so I'm assuming he's been bitten. Going to give the little fella frequent soaks and see how things go