If a heating pad feels warm to the touch, it is likely already too hot. When I touch my heating pads I can just barely make out any feeling of heat at all (if it weren't for using thermometers to monitor them I'd probably be tricked into thinking they weren't even working)
Go to home depot or wal mart or a store that carries thermometers (for measuring outdoor air temps). There will be digital ones that have a wire running out of it so that you can keep the thermometer unit itself inside your house and run the wire out a window so you can know the outdoor temps. They run somewhere around $10. Take the wire that you would run outside and run it to the inside of your cage and attach it
directly to the glass, directly above the heat pad. (your snake will be able to lay on the glass so this is the most important temperature to monitor...not the air temperature. (Note that on the thermometer unit this will be read as the "out" temperature)
Secondly, you will need a thermostat to control the temps. Some examples:
http://www.spyderrobotics.com/products/herpstat.html
http://www.reptilebasics.com/ranco-etc-111000-pre-wired
You plug the heat pad into the thermostat, and plug the thermostat into the wall. There is a probe for the thermostat that will also go directly on the glass inside of the tank, directly over the heat pad. It will maintain around the temperature you set it at.
To sum up: There should be 2 probes inside the tank, directly on the glass, directly above the heat pad--Thermometer probe, Thermostat probe.
IF you don't have the money at the moment for a thermostat, a quick solution is to use a lamp dimmer switch you can pick up at a store like home depot. (Though I'd still recommend getting a thermostat as soon as you can). You plug the heatpad into the dimmer switch, plug the dimmer switch into the wall socket. You then have to play with the dimmer switch, moving it up and down, while watching as the temperature goes up/down on your thermometer until you find just the right setting. Note that if the temperatures in your house fluctuate, the temperatures of the heat pad will fluctuate if you are just using a dimmer switch which is why I wouldn't recommend them for long term use. So you could move the dimmer switch a tiny bit...wait 10 minutes and look at temperature on thermometer...move dimmer switch a tiny bit either up or down...wait 10 minutes...repeat.
The overhead light/heat doesn't even really need to be used for cornsnakes. The air temps in my own house tend to float around 68-70 degrees in the winter, which is the air temperature of my cages because I don't use any overhead heat for them. They just need the belly heat (heating pad) for digestion. And like someone else stated, unless you have any problems with shedding you don't have to worry too much about the humidity. In fact, your humidity is probably higher than mine runs in the winter time and I rarely run into shedding issues.
The last thing I would recommend is to give your snake some time to chill out and get used to its new environment. When I get a new snake, I put it in the cage and don't even handle it once for the first week. After that for about the first month I generally only handle it to feed and do a quick inspection. Hiding is
very common for hatchlings. It is a new environment, they are freaked out. To them, you are a giant predator. It is actually pretty rare that I even see hatchlings in their cage until they are about a year old or so. Most of the time they crawl through the aspen shavings and hide. It is also very rare I ever see any of my snakes drinking.
With it having already regurged, it is very very very important not to stress the snake out any further than it already is. Do not try to feed it right away or the chances are higher it will regurge again which can become a dangerous situation. Do not handle it. Let it hide, because it will feel safer when it is hidden, and reduces stress. When you do feed it, if you want to avoid any ingestion of the bedding you can feed it in a separate small rubbermaid type container, and then move it back to it's enclosure after it is done eating.
There is a regurge protocol listed somewhere on this site and after I finish posting this message I will go look for it and post it for you to read or if someone else finds it before me they can post it.