Question about 12on/12off, first time grower

I installed my timer yesterday, but failed to realize that I turned a standard ceiling outlet light on to do so while my 1000W HPS was unplugged and failed to remember to turn it back off before sealing up my room. I got home from work today and realized my mistake and turned it off. I've been told to not let any light get in my room while budding and the light is off for 12 hours. I turned the ceiling outlet light off and let the 12 hour off cycle continue. Will having this light on for the first 8 hours of my 12off cycle affect anything if it is only one time? Just curious how much harm this could do if any at all, being it only happened one time.

I'm new to growing too, but from what I've heard this will probably set you back a week or 2......... Just because the plants get confused and they have to "re-configured" themselves.

Thanks for the input.

You may have caught it quick enough, I wouldn't worry about it. If it was the first day then no harm should come, will just start a day late.