Soft Lump, should I call vet?

[Funkyfilly024]

just noticed it today, its soft, she windsucks if that has any bearing, 11yo TB

photos here and next 1 after:
http://www.horseandhound.co.uk/forums/picture.php?albumid=1117&pictureid=9259

advice, possibilitys, should I call vet or wait?

thanks

 

[Funkyfilly024]

http://www.horseandhound.co.uk/forums/album.php?albumid=1117&pictureid=9258

2nd photo, also she is out on grazing 24/7

she isnt my horse, sister says its normally there but looks a bit bigger today

 

[Marilyn]

Is she eating OK/dribbling or anything? Has it come on quite suddenly?

 

[Funkyfilly024]

no seems perfectly normal, eating and everything, I think maby it is a sting :/
my sister says its always like that but i dont know it just looked bigger today,maby i never noticed it before, do some horses just have these?

 

[Ella19]

could be a tooth abscess?