Strange lump

[Jadesky]

My horse has a lump on the side of her cheek not sue if maybe its her teeth but its hard and round like a golf ball but isnt stopping her from eating and dosent hurt her when i touch it any ideas?

 

[Lintel]

Is it on the jawbone?
If so- join the club
My post:
http://www.horseandhound.co.uk/forums/showthread.php?t=526533

If it's the same as my boys x