replacing your Jumpstart for the UTH is the right direction, but it does not need to happen this second. you're okay for the time being, but the sooner you can replace your Jumpstart with a reliable thermostat, the better. a Jumpstart failure is not an if, but when.
however, your immediate next step is raising your ambient temps, and that means getting a CHE, ceramic socket dome and thermostat for it. the size/wattage of CHE you'll need depends on the size of your enclosure: when i ran a 20gal glass, i used a regulated 100 W CHE (on a rheostat, which i do NOT recommend for your environment). 100 W is a bit more power than needed for that size enclosure, but i'd rather run a higher watt element on low power than a low watt element on high power.
LINKS:
Herpstat thermostats (Cadillac of thermostats; well worth the money and will last for a snake's lifetime)
100 W CHE (available at most pet stores) depending on your enclosure size this might need to change.
Ceramic socket dome for CHE. i did not include a link here bc idk what size enclosure you have. just be sure whatever dome you buy: 1. has a ceramic socket, and 2. is rated AT LEAST 100 W to be used with your 100 W CHE. but again, idk what size your enclosure is so maybe 100 W might not be the right size.
hope this helped!!! again, if a second thermostat is a true issue please lmk. i might be able to help you with a temporary solution.