How old is your tank and what lighting are you running? The lighting looks very white for most reef tanks and the sand/rock looks pretty clean so I can’t tell how established it is. As much as I hate to say something like this about any animal, you’re honestly probably better off with it gone if it were to die. These are extremely aggressive, even more than carpet anemones. They’re one of the few anemones that can cause damage to people with very short contact.
Back to your specific nem though. Assuming your lighting is sufficient and the tank is at least a few months established, I would try and move the anemone to a low flow area where it can try and heal up because as said above it does look like there may be a tear. All of my anemones have healed from that (BTA, flower, mini carpet) with nothing but a single mild iodine dip to disinfect the wound in case of bacteria and then being in a healthy environment for two weeks or so.
