First egg of her life!!!!

So this is an odd story. Ive had my one female going on 5here years now. Never once has she laif an egg. Never shown signs or anything. She has been in the same tank with the male for 3 years and still nothing. The past weeks she has been paling around with the male and her tail had thinned out and i thought oh s$%* impaction.....then i get a call from my fiance on the way home from work she laid an egg...low and behold there she is face deep in water drinking like a maniac with a perfectly full plump white egg in the sand. Its been 16 hours and it hasnt drooped or anything. Still the slightest bit soft but i have it in a diy incubator since i wasnt expecting this. I was lucky to have a zoomed hygrotherm some spare uth's and a foam lined box from a gecko i got a few weeks ago. Found some vermiculite and a plastic tub and lid and set up the uths in the foam box, did a 1:1 of water and vermiculite in the tub, set the egg in and put the lid on. Set the probe in the tub with the egg and placed it in the foam box with the uths. Problem is the probe got condensation and threw an error code and stopped regulating the heat early this morning i guess. My mechanical thermometer said it was 81 in the foam box i have the thd tub in so i moved the probe in to them foam part to dry. Will the egg be ok with a short temp swing like that till i can get home to right it? I had it maintaining a perfect 87+-1 temp. I know since this is the first one the egg might not be viable but gotta try it. Any thoughts?