A delay like that is no big deal. Since hCG stays in your system for about 72 hours, very gradually reducing over that time period, having your shot a little early or late by a few hours doesn’t really change anything. The only thing you might notice if say 5 hours goes by is that you’re a little bit more hungry but once you take your shot you should feel better.
If you’ve forgotten your shot for most of the day, at that point it’s probably best to just call it a “skip” day and resume your shot at the normal time the following day.
