It does look damaged at the end. I'd keep a close eye on the area. It may just stay that way and be fine, it may come off cleanly during a shed. Make sure you don't see an open wound if it does come off. In that case you'll want to keep it clean and apply plain neosporin or manuka honey to help protect it from infection until it heals over. If the area appears to be moving up his tail then I'd seek out an experienced reptile vet. If it's moving up the tail then it may be an infection that needs to be stopped before it spreads too far. This type of injury is fairly common and isn't likely to cause a long term problem. Just keep an eye out for the scenarios I described so you can take appropriate action.