Any idea how to stay cool at night?

Have you tried sleeping naked, not using and covers, with a fan blowing and the window open? 

Find a few sreggin to wave palm leaves.

Do not use any blankets at all!!!  I can't tell you how many people complain they are hot at night but cover themselves up.  

Take a cold shower before bedtime.  However, you really should see a doctor in order to find out what's going on.  

Try googling what a fan is used for. 

Sorry to hear about that. I can relate to a degree. I keep the AC cranked down to about 60° F/15° C and use a large fan. 

 If you're sleeping on a foam mattress (or pillow) it could be exacerbating the problem (even people who don't run hot can become overheated when using memory foam mattresses). Try sleeping on the sofa (or anywhere else) to see if the situation improves. And if you have memory foam, consider a new mattress.

I use a mister whenever I wake up and feel overheated. Not a sprayer - misters have a very fine mist that helps on the face (or where ever). Misters are very refreshing and cooling.

Try freezing water-filled hot water bottles and using those in strategic places (under the neck, back, knees, etc). I learned this while recuperating from a bad car accident and was using the frozen water bottles to help relieve pain but they also cool you down a LOT. I use sturdy hot water bottles by Fashy (it’s a good idea to use thicker and stronger ones that can withstand constant freezing). In a pinch, you can always freeze actual water bottles (Evian, Fiji, etc.) and use those to cool down.

Check medications (Rx or OTC), hormones, or supplements that may be increasing your heart rate.

Lastly, breathable, all-cotton/linen/all-natural sheets and bedding (along with non-synthetic sleepwear) are important. 

Open a window, get a fan.

Your bedroom should always be the coolest room in the house for best sleep.

While it's cool outside i leave my window open and a fan moving the air while using a thin sheet only and sleep very well.

I sleep well below 65 degrees in the room.

Lowering the humidity in the room is a must.

If you are able to sweat then your humidity is likely way too high.

Your bedroom humidity level should be 30-40% max for best cooling comfort and i keep mine at 30%

i think you should get consult from the doctor cause its not something that you can ignore before it getting worse.

Maybe apply cream or face wash or mineral oil