No signal after replacing battery?

Hi there, was wondering if you guys could help me? I'm very much aware that I may be screwed here.

I dropped my phone in the sink and removed it almost immediately, I turned the phone off and put it aside. I should probably mention that I've repaired iPhones in the past and had all the tools at hand.

Alarmingly, out of know here, the phone started hissing. It was also boiling hot to the touch. I panicked and hastily removed the battery, (probably not the best thing to do, but I was genuinely worried for my safety rather than the phone) . Whilst removing it, the battery secreted some gas and it genuinely felt like a dangerous situation.

In any case I dried out the phone and replaced the battery with an official Apple one. My problem is that the phone is running hot (where the processor is), draining battery quickish and is

Unable to find any cellular signal. Other than that , the phone seems to be running fine, do I have options here? Or is it a write off? Is it worth replacing the antenna cable? What other things could be causing the signal issue? I've tried hard resetting, toggling aeroplane mode etc, any help would be greatly appreciated :-) cheers!