Replacement screws for mi2?

[e-r-a-n]

Hi, after several replacements of defective parts my screws heads condition is really bad.
Where can I get a replacement? I don't know the size and couldn't find it online

 

[paulrlz]

What do you intend with "screws head"? The front panel of the phone? (Not the screen)

Inviato dal mio MI 2S utilizzando Tapatalk

 

[e-r-a-n]

The top of the screw.
I need to replace some of the screws that holds the back cover (beneath the battery)
P