They can regrow their tentacles, and really you've made it through the most critical time... I would keep it in an area of pretty good flow... This will decrease the likeliness of it RTNing on you (Rapid Tissue Necrosis) If you see it start turning brown and "melting" on you, its a goner... You may want to subdue the lighting while it is healing itself as well... DON"T put it directly under any Metal Halides... Hope this helps...