I need help with my phone; the screen is glowing all blue yet it hasn't gotten water damage..?

My phone is a Verizon Wireless LG and it's about 4-5 years old and I just got it this past Christmas so I haven't had it long. My step-dad had it for about 2 years and then my brother had it for 1 year and now I have it. Well, this started about a month and a half after I got it: The screen when I turn it on it supposed to be white and say Verizon Wireless but now it's all blue and I can't see anything. Then once it's done turning on, I can't see my screen, so I can't read texts or look up my friends' numbers. It rarely ever works now, and yes, it does have full battery. About once or twice a week it turns on so I can see my screen. But I have to keep my phone open or else it will turn blue and I won't be able to see anything. Then about an hour after it's been on and working, it just turns blue out of no where. I don't know if this has been happening because it's old, or because maybe I've done something wrong. And it hasn't had any water damage so that couldn't be a possibility. Can someone tell me how to fix it or something that's probably wrong with it?? Thank you.(: -Lexi