<s>[INST] My dad had a stent put in last October.  Up to then he has been very healthy and active and keeps fit with weights and bicycling.  He  is 73 and has been experiencing a warn sensation on his face, specifically his left cheek.  He is on medications and none cause this side effect.  He did have a test to see if the artery in his neck was clogged and it wasn't.  What could be causing this?  He usually feels this in the morning and it comes and goes.  Also, are there any other tests he can have done to investigate this further? [/INST] Hi,It may be an allergy, or maybe he sleeps on his check, or here is something that irritates the skin. Try to pay attention what he does in the morning, what causes the warm sensation, how he sleeps, if there is something unusual at home or he has changed some habits. It will help to find the cause.Take care </s>