Since you both made an effort to contact each other, I think I would leave it at that.
If he used, you will know soon enough and it won't take a phone to tell you. If he didn't then leaving it be will give you a good day of peace rather than a wasted day of fear. Wouldn't you rather have a good day?
He will use or not use no matter how many time he does or does not answer his phone and my thoughts are to just let go and let time answer your question.
Just my thoughts.
Hugs