Injured anemone

We have a green bubble anemone that has been thriving for about 9
months. Unfortunately, it somehow got a big part of itself sucked
through the grill protecting one of the powerhead intakes used for
circulation. All of the tentacles down one side were ripped away.

This happened about 3 days ago. Since then, it has curled itself around
the injury and seemed to be just getting on with life, with the
remaining tentacles behaving normally, grabbing food at feeding time,
etc. Mouth also opened at feeding time as usual to receive the food.

Today, it looks very limp. The two clowns that are its companions are
acting confused and a little stressed. Also, the mouth did not open
fully at feeding time, even though the tentacles still seemed to grab
the food.

Is this the beginning of the end or is there any chance of recovery? Is
there anything we can do to help with the healing process?

Any advice gratefully received.

Cheers
Dale