Does anyone have experience with splints?


So about a week ago, I found a thumb sized lump on Oz's shin, below the knee.
He hasn't worked a lot, because the ground is so hard, and he's 13 years old. I can't imagine he would develop a splint from lounging in the field -- unless he's been kicked. (We do have a very nasty cob in the field.)
I've been hosing his leg, the bump is warm, but not hot. He's not lame -- which means nothing, because he will only limp just before his leg falls off. (That horse has a pain threshold and a half...even my vet said so.)
He hates boots of any kind, and I wouldn't feel comfortable turning him out with splint boots on, anyway. 
For now I'm hand walking him (ground still hard) or do very light work in the barn, when it's not totally boiling in there.
I cannot get him to put his foot in a bucket (it'll bite his leg off, don'tcha know?)
Ice packs, twice daily? (Morning and evening?)
Any other suggestions?