Help me please!

[Aronasmalie]

Hello!..I'm just asking here about my iphone 3gs..I just sent my phone to a repair shop yesterday..An earcap was stuck in the earpiece..Then it costs me 45dollars.. Then to my dismay,when i took it home..The screen became bluish in colour..I still can see the images inside the phone but i know the light is rather dim not brighter than before..Because as far as i know from watching youtube videos,the screen and the back parts are separated right?I mean,there's nothing to do with the lcd screen..But,I also found out a small tape near the screen which is absurd!Please do tell me why this happened?Is there a chance that the repair guy changed the lcd screen or maybe because o his carelessness handling the motherboard?Thank you very much for your help =)