Runny nappies teething?

I'm phoning the GP in the morning but posting here as I can't stop worrying now (I've gone down the rabbit hole!) My 5&a half month old has had super runny dirty nappies for a while, we are wondering if anyone has encountered this before. We are talking coloured water, they're that runny :( They are also extremely acidic - he had a shart during the night, it was max 2.5 hrs between one nappy and the next but sleeping with it on his skin gave him loads of irritation. We are using metanium as we used that successfully before, and it calms down overnight and then the next day he poops and it flares up again even if i get the nappy within 5 minutes of the last noise/grunt. Anyway, we initially thought he was teething as drool has really kicked into overdrive, he has flushed cheeks even if he's not warm anywhere, he is obsessively sticking everything in his mouth and he relaxes if you help him massage his gums. He would be a little fussy at times and we started putting bonjela on his gums, I *think* that's when the super runny nappies started.. He would only poop once and be done, and he has been eating/sleeping fine and he has been happy and chatty and active, doesn't seem bothered in the least. But today he's gone 4 or 5 times and he's been struggling with trapped wind for the first time in months? I stopped giving bonjela on Monday but as it now seems worse I don't think that was it? Both me and partner had a stomach thing but it was super mild and it started after he started being unwell, and his is continuing when ours stopped after a bit.. Just unsure if teething is the cause, Internet says yes and no! Or a bug he's still fighting? What should I look out for/do to help? Any advice welcome :(