When i got the Chessie from G.s friend she had a lump on the back of her neck. The skin got very hard and the hair started to fall out in a small patch. When that happened I knew right away what it was. I have had other dogs and a few cats get this. I was always told its a type of bot fly infection. The fly lays an egg under the skin and a abscess forms and the larvae comes out. I thought it only happened in spring and summer time though. Since I got her it ruptured and drained. I have been washing it with hydrogen peroxide and soapy water. It looks to be healing up. The little dog we had had this when we first got her. she got this lump under her skin and it got to be about the size of a egg yoke. One day she was running around with me and she let out this yelp and the thing ruptured and squirted bloody pus about 2 foot out. It had a little hole and after it drained it healed up real nice. I have heard some guys slice them open where the skin is thick and hard to help them drain. When the skin gets thick like that it loses all feeling. Is there a spray that prevents this? has anyone else had this problem?