Kitten wound

My mums kitten got neutered on Tuesday the 21st may. We have just noticed this wound on his front leg. It’s in the shaved area so think it’s possibly from when they put him under. He’s eating drinking and acting fine he’s just cleaning it a lot. I’ve added a picture. He’s 9months old. I’ve added a close up and one from a bit of a distance so can see the actual size  any help is appreciated

that's so painful i wish she got a good care on Kodi  

Hello!  And thank you; really helpful pictures. This area looks swollen, inflamed and possibly infected; hopefully your vet is aware of it by now, but if not please get in touch ASAP because infection involving a blood vessel can be a real cause for concern.  My first idea was a cat-bite abscess - the area surrounding them often goes bald - but on reading your text, if a canula went in there than infection from a canula or a drug reaction is obviously also high on the differentials list.  Pkease will you let us know how you got on?  Thanks