that sucks man, it adds abit of stress to the plant but nothing to worry about. the worse that can happen (if it happens again) you would need to restart flowering again which means longer flower period. i can suggest for you to get a light timer so that wont be a problem itself. on my first grow i didnt use a timer since i had lots of time and so on. a few times i lost track of time and didnt give it the proper 12/12 instead the timings had to get change in result flowering took double the time... please invest in a timer so it wouldnt happen to you.