Do we call an ambulence? And what are these symptoms!?

my father who is curently recovering from lukemia has recently been in alot of pain he gets really serious muscle cramps quite a few times and like an attack every time it happens he says his in a great amount of pain, he also has been getting a rash on one side of his face. This has been progressing for about a week now and we're really scared since he hasnt been able to see a docter due to his fear of an attack occuring while he drives, and no one in the house can drive either. I am unsure weather we should call the ambulence next time it occures.