swelling on side of hock

[CBFan]

3 weekends ago (so 2.5 weeks) my boy had a 'ding-dong' in the field when I tried to introduce him to a new herd. this resulted in lots of kicks and scrapes and pretty severe lameness (i'd say about 7/10ths)... he was buted for 3 days and on trot up he was sound although still pretty lame on a circle (about 4/5 10ths lame) this has improved but he is still lame and I noticed one hock (at the pont of hock was pretty swollen). there is also swelling up the inside of the leg from the point of hock. any ideas what it could be? photo attached. I'm in talks with vet at the moment but just wondered if anyone had seen anything like it before. just to make it clear, it is the 'highlighted' silvery area...

 

[Izzwizz]

Could just be the fluid surrounding the joint still protecting it thats made the lump. A horse I used to look after got a kick to her hock and turned out she had a piece of bone chipped off. If your vet hasnt been already it may be time for xrays bearing in mind the time that has passed since the kick.