What I would probably do is place the snail in a breeder trap if possible, that way it isn't doing acrobatic movements for the next week or so. Also, if you can, and depending what the tank temp is, lower the temp to about 74. This will slow its metabolism down in order for the shell to repair itself from the inside out. Do water changes to keep the quality PRISTINE, and feed tempting foods rich with calcium to keep it eating. Depending on what the picture shows (its hard to get clear ones of the suckers sometimes), you may or may not need to patch. Do you see any soft tissue exposed? Does the crack look "tight" or does it appear to be "looser"?

