I thought that too but it is not getting smaller, in fact it was a small patch around the bump and now it's half his face, unless all that area was damaged and now its showing signs, either way he got the bump for a 3rd time, so there must be something causing it.The gray patch could be scarring from an injury or the infection he had.
The swelling and the bump are gone completely. I can't keep him in the quarantine tank for too long either because he is so bored by himself and keeps staying at the bottom dragging himself and scratching his fins and tail, started having some fin rot, but it heals very fast when I put him back in the main tank (he swims perfectly fine and eats when I keep him company, no breathing issues, no bloating etc., it's just boredom, I keep the quarantine tank really clean and use remineralized RO water in there too and testing the water quality).