Wow that is a tragically unfortunate turn of events! Yes just keep an eye on him and make sure he still has the ability to eat. Most fish have a slime coating which should aid in that glue being removed overtime. Also IIRC some fish "shed" if you will, their outer coating sometimes like when they're sick to remove parasites. Feel like I read that once before. never the less, long as he's eating, I see no reason why he'd be in any danger.
However, if for an emergency situation you ARE forced to catch him, DO NOT use an x-acto knife. Use a sewing needle. It's much more precise but more blunt so chances of accidental injury to the fish is reduced. Though catching a tang would be more difficult than glue removal most likely anyways.