Night terrors or just nightmares?

Chasity

My little guy will be 3 months next week and for the last month or so he'll start screaming during a nap. He doesn't wake up and giving him his pacifier doesn't usually calm him down when this happens. It only happens maybe twice a week or so and never at night only during a nap. We'll be asking his doctor at his next checkup but that's over a month away and I wanna try to help him before then.