The bottom is usually cooler than the top. If you bottom temp is 80 then your top and basking gotta be higher than that. More than likely too high. how old is your cham? You humidity is good but really you don't need to mist that much and you need to give the cage a chance to dry out especially at night. You know that there is no misitings at night and no lights on. Make sure your cage is completely dry or close to it before the lights go out.
you need to know what your upper cage temps are including your basking. She may be too hot and that is why she is staying toward the bottom of the cage. They normally like to be high up in the cage. Females usually only go toward the bottom if they are getting ready to lay eggs and she is too young for that! You cage temp should be in the low to mid 70's and your bottom temp cooler than that. You need to do some adjusting. What are you using for lighting both UVB and basking?
She probably walks on the bottom a lot as it's the coolest place. The hottest temp for a baby veiled is around 80 at the warmest (usually at the top of the viv). Babies are not able to thermoregulate like adults can, so should be kept with a hottest temp of 80 until approx 6 months of age, and females should be kept between 80 - 83 as adults.
I would remove the basking light altogether. She will not need a basking light if your cage temp is that hot but it is most likely being caused by the 50 watt you are using which is too high. As Miss Lilly said a baby should be kept no hotter than 80. Take out the basking or cut it back to a 20 watt and check your temps again. what is the cage size?