My display brightness won't adjust

I had my LCD screen replaced with a new one as the old one got damaged. A day or two after collecting the phone I realized my screen brightness would not dim and that the dim on the brightness index was still bright. It is off auto brightness and I tried the Zoom filter trick for low light and it hardly helped. Basically, my phone won't dim and is still bright when it is on low brightness. As a result of this problem, my battery will drain 100% in an hour and my phone overheats after 10-15 minutes of use.