@anadelmar first do not turn on your phone, charge it or try to connect it in any way. Remove the battery as soon as possible from the phone to minimize further damage. After that completely disassemble your phone by using [[Topic:Samsung Galaxy J7|these guides.]] Using 90%+ isopropyl alcohol, clean your phone by following [guide|5825|this guide.] It was written for an iPhone but all the points are still pertinent to your phone as well. While cleaning, check for obvious missing or damaged components. you can always post some images of your boards etc. with your question so we can see what you see. Use this guide [guide|21499] for that.
Once it is properly cleaned, replace the battery and reassemble your phone. then you can properly troubleshoot.