I had this happen once with a blu 5.3. And it was because i had it charging on a laptop then because i didn't disconnect it properly the phone turned off and would turn on. I fixed it by letting restarting the computer and letting it sit there eventually about 10 mins later it powered on and i disconnected it properly. The thing i would try is hooking it up to a different charger altogether. See if any lights come on or anything. After about 5mins push and hold the power button. Again wait for lights sound etc. If nothing try a reset. You hold down power+volume up+home OR power+volume up+volume down. Let me know if anything happens.
If it fell and was submerged depending on what type of water it fell in would tell you what you could do. you can take apart the console and check the connections if you see salts built up wash them off with demineralized water. use a good electrical conducting oil to lube rusted connections.