R2 Trigger on PS4 Controller not working Fix/Solution?

[SoraxTidus]

Hi, I need your help with my Black PS4 Controller. Since April 2018, while unpacking my stuff including my PS4 console, the plugs and my controller, my controller has some problems like left joystick was loose moving, the Start button needs to press harder than it used to and one of the right trigger buttons don't work. After my Mom fixed my controller, the left joystick and the start button were fixed, but not for the R2 trigger button. In other words, it's not activating. Is it there a way to fix the right trigger? I just want to make the R2 button working again. Also, I don't know how to fix it as well. Please Reply Me Soon. See You Later.