mobile

Can someone help me please? During phone calls and its only on lollipop my screen goes black and it won't turn on until the call ends but its only in the sunlight, at night time or in a dark room it doesn't happen anymore. My screen is cracked and some pieces of glass are missing on the top around my ear piece are missing so I'm assuming its a proximity sensor issue. I don't have this issue on TW roms since I can turn on the screen with the home button, but can't on lollipop roms. I really don't want to have to go back to TW but this is a major issue with me, is there anything I can do to mess with the proximity settings or anything? Obviously get m screen fixed but moneys a little tight on my side so yeah. Any help would be appreciated