I think you should consider getting a new battery soon, I once teared down a battery to see what was inside and it's basically a lot of compressed layers of what ever the inside of a battery is made and that's basically where it keeps the electricity from when you charge it so I'm pretty sure that the little hole you made will slowly reduce battery until it can no longer charge plus it will also expose your phone to those toxic chemicals and I'm sure that is not good for y]the phone and as for the smell it turns out that depending on the amount of usage you have given it(charging and killing the battery) makes it produce a different smell because out of the many that I have teared there was one from an ipod touch of about 8 years ago(a few years have passed since this happened so more about 12-15years in total) smelled really good

compared to a battery which was practically brand new
so in little words yes you should replace it asap