The answer to both is probalby not, first, did you install a fermentation lock? how much head room was left after you filled the bucket? if you have head room and you installed a way for the co2 to be released why did the top pop off? reinstall the top and see what happends I bet you'll be alright. In any brew session there are mistakes some are pretty bad all I do is correct the best you can and almost always things turn out right or should I say alright.