Why didn't you take what was left of the first vial and then go into the second one?
Also, it depends how much less you used and what your dose is supposed to be. But I doubt that it will have any negative effects, just less positive effect. In other words your changes won't come as fast for the next week but you also won't revert back to any female traits.
I wouldn't even bother contacting the endo if it's just one dose. Very likely not a big deal.