Some snakes really have crummy aim some eat backwards and some are just normal. If this is not a change but just a worse day of a string of bad days it isn't something to worry about.I have two with really poor aim and one 99% of the time eats backwards. So much so that he gets light meals as he simply cannot eat anything close to 10% of his weight it gets stuck at the hind legs.He is dopey. Lucy our one eyed snake has got to hit the head or she will drop it she tries to start where she hits, period, no constriction just swallow it now. If it is in the middle she will carry it around like a dog with a bone for a bit before she drops it. They can be unique.