So I need some advice. My house is going to be abnormally cold tonight. I usually keep it at 67 over night, but for the evening I need to keep my windows and doors open to air out my house (10 year old trying to cook...) Would it be overly disturbing to turn on a red heat lamp for one night or would she be okay at temperatires in the mid 50s for part of the night? I know the ideal would be a ceramic heater, but I can't go to the store right now.
Does she have a hide so that way the light wouldn't bother her? Otherwise yes, the tiniest amount of light can disturb their sleep. If you have any heat packs or a heated water bottle you could place them underneath a blanket in her terrarium and set her on top (check temperature first).
Honestly, if it's just for one night I think you should be good either way.
Since I am kinda paranoid about cold temps due to a childhood incident, I would personally air on the side of turning on the light, but real talk 55ish should be fine. Guac has been under those conditions a couple times due to my folk's power going out and he hasn't suffered any as near as I can tell, but also one night of disturbed sleep shouldn't be a huge issue either, particularly if they have a hide.
I would probably not do any form of head pack unless you have ones specifically made for reptiles - anything else is dangerous. Same goes for heating pads, and even then make sure to use a thermometer. Hot water bottle should be fine, though, figuring it's not hotter then you would otherwise expose them to at the start of the night and they can move away from it.