Can a fridge and water cooler be on the same outlet (both on full power are quite less than 15 amps)? What if it's a split receptacle so each is on their own circuit? Thanks

I was spraying for bugs on my counter and got some on the gfci receptacle. I assume there is some type of short or other fault as indicated by the loud buzzing and puffs of smoke. It apparently thought it was enough moisture to pop out the reset button. I was able to push in the red reset button, but if I push in the test button there is a light buzzing/sizzling sound. No more smoke though. First, why would it continue to do that if the gfci was tripped? Only if I flip the actual circuit breaker would there be no buzzing when I push in the test button. Second, is it enough to just replace the receptacle? How can I tell if the wires are ruined and need replacing? Will they look burnt? If they are can I just cut the burnt part off and restrip when reconnecting? Is this something I can do myself? Under normal circumstances I can change switches and receptacle etc. with no problem. Thanks for the advice.