Lithium-ion Batteries can swell causing the Trackpad to push out and the case to separate, but this is not technically an explosion. As far as "explosions" go, at worst a Lithium-ion Battery will sometimes catch on fire, but this is extremely rare and usually caused by a defect internal to the battery. Sometimes a Lithium-ion Battery will begin to swell if the Battery was left with 0% charge for an extended period of time which can cause permanent internal damage which sometimes will lead to a swollen battery once the battery is charged up again. Apple does not consider a swollen battery to be safety issue.
If your laptop is working fine, then just continue using it. You may find that the liquid damage caused corrosion to some components which over time may cause the laptop to fail, but any damage has already been done so you may as well use the laptop for as long as it continues to function. It is really hard to say since every liquid spill is different.
If you have the 15" model, then see if your laptop qualifies for this Apple Battery Recall program for a battery fire safety issue with a small number of MBPro 15" (2015) laptops:
15-inch MacBook Pro Battery Recall Program - Apple Support
FYI, here is the current list of the publicly acknowledged free repair programs for various Apple products (some products may have multiple programs):
Apple Service Programs - Apple Support
