Could my temp gage gone bad or the thermostat

Okay I’m currently have a 2015 Nissan Altima s 4 cylinder
, about last September she got in to an accident taking
out the radiator, core support, fan assembly, condenser w,
etc , however there where was no other major damage to
engine or anything like that . We replaced all that and now
she not leak or anything coolant seems to stay about
same level , however my temperature gage is hitting hot in
the matter of minutes , especially if taking highway , when
pulling over letting cool down and just basic check
everything seems fine (no smoke ) and doesn’t feel hotter
then normal temp , I’m just wondering if this could be a
faulty sensor or a thermostat , seeing how we didn’t
check those in the process of fixing everything . Any
thoughts or ideas of what to check ? And is it okay to
continue driving until I can get if fixed tomorrow