colt with swollen cheeks/jaw

Question
Hi there! I was wondering if you could help me out. I went out to feed my 3 horses this morning and noticed that my 10-month-old mustang colt's cheeks and throat were swollen. It feels like they are full of fluid, and they are warmer than the rest of his body. He is acting completely normal, no dullness, tiredness, nothing out of the ordinary. Eating fine. No loss of appetite. What could this be?? I don't want to think that it could be strangles... can you think of anything else?? This has happened before, but it only lasted a day and then went away. He was an orphan, so his immunity is not at it's very best.
Any help would be greatly appreciated! Thanks, Hannah :)  

Answer
Hannah,
I am not a large animal tech. Something random like this is most likely an allergic reaction to something either in the feed or she is getting bit by something, but you cannot risk it with a horse.

I would definitely call your vet and have him looked at.