My young English setter has a lump on his head it has been aspirated and no sign of cancer [ six months ago] but it has come up again I 've seen a Vet who prescribed antibiotics and Preds [to bring the swelling down] then he wants to remove it... but my other Setter won't leave it alone and I have to be with them both 27/7 or else the older dog licks it and makes it bleed! Have you any suggestions of what I might use to deter the other dog? I have tried putting euclyptus oil near it [not on it! Obviously] but nothing seems to deter the other dog easily! I will have to separate them tonight, as al day it has been fine and then in the last few minutes the older dog has made it bleed again!. blow!

Why would you put eucalyptus oil on a wound? To keep the other dog from licking at this sore, I would think that getting Bitter Yuck would work better. It's a water based deterrent that tastes pretty bad. You can spray it directly onto a sore.

I'm not sure I understand.. your vet wants to remove this sore but wants to wait until the swelling is down? If your other dog is making it so that the swelling won't go down, I would suggest to separate the dogs completely until this surgery is done and your dog is healed. This may be a few months that you have to do special treatments for both dogs.

Are either of the dogs crate trained? How old are the dogs?

I would crate the one with the sore when you have to be away, thereby keeping the other dog away from the wound. If they're not crate trained, then put them in separate rooms when you're not there.