What do I do? 😭

Da

My son is a very happy baby. Everyone always comments on it. He's only upset if he's hungry, tired or bored. And he's been sleeping through the night for months. He just woke twice out of sound sleep crying hysterically. No fever. Checked his digits for any hair tourniquets and didn't find any. No rashes. Hell only settle to sleep if my husband is holding him. We have him Advil and another bottle and he was still upset. So my husband is rocking him to sleep (something we haven't had to do in months). When should I know to take him to the hospital? It's not normal for him to wake up crying like that and not stop. Even when he's sick I can always get him to settle.

Edit: I think I figured it out. I think he's got the beginning stages of a diaper rash. He'll be a year old in a week and he hasn't had a diaper rash so I didn't even think to check. My hubby diapered him before bed and this morning so I didn't see it until just now. Red and inflamed in his butt crack. I used some aquafor. That's what my husband puts on every night after his bath but for the last few months when I've seen him do it, he does it half ass and just kinda puts tiny dab on his butt and I lecture him about it. Guess he'll learn his lesson now!