Not well ..
But it can do another
Put it in a well place not sand
And see if react to light and to touch and if close well or remain open in the low side
okay i picked it up and moved it it did react and closed up tight. I placed in it in a new spot, and it is starting to peak out... hope it is okay. it has been finicky since i got it. I just cant seem to make it happy. I have nice flow and light I my tank could it be too much?
Hard to know for sure if that is actual foot or concentrated byassal threads. Clams do not sustain foot damage unless manipulated by some means, larger fish, larger invert, hobbyist.
Check for Pyramids snails at the base, post a day light image when able.