Stop using your device, go to a computer and Google "android file recovery". There are a number of tools available, but have no clue as to which is best.
Android is no different than other file systems. They have not been erased... their entries in the file system have just been removed. The more you use your phone (and the more it writes to storage), the more likely these files will be overwritten because you told the system you were done with them (when you deleted them). If you had plenty of free space, and have not done much on your phone since you deleted them, you have a good chance to recover them.