Dude, worried about a tip?? I've had multiple RBTA's get half destroyed by powerheads or filter pickups. Literally CHUNKS of meat laying around the tank. Usually they hide for a day or 2 after the incident, then just start regrowing the meat and are not bothered by the chunk missing.
Actually happened in a tank a few weeks ago, intake to the fluval 404 had never been a problem so it isn't covered with foam or anything like my powerheads. Well I did a large water change and had to move the rock it sits on, well it didn't like that so it went on a 2 week voyage around the tank. Now it has a small area that is growing back, but not a big deal.
Realy, 1 tentacle no worries. If you see chunks everywhere it probably got friendly with a powerhead.