Screen wont turn back on unless phone is cold.

My galaxy s9 is acting strange. I can be on it for hours and all is good, but when i put the screen to sleep , the screen wont come back on. The phone still rings and works, but just black screen. If i put the phone in front of an air conditioner, it will work correctly after a couple minutes.

It has never went black while im on it, only once i turn the screen off. The phone doesn't get hot to the touch, but i think its a heat issue since the air conditioner trick works.

Any ideas ?