Where can I buy Focusing Screen for my Nikon D3200 DSLR here in the Philippines?
I tried cleaning my focusing screen and unfortunately, I accidentally dropped it and now, it is scratched all over and I'm annoyed whenever I look into my viewfinder. I badly need to have it replaced.
The focusing screen is not meant to be a user-replaceable part on the D3200. You aren't meant to remove it. Shops will not stock them. A photo specialist may be able to buy in and fit one for you or you may have to contact Nikon directly.
Unfortunately I think you are calling the LCD a focusing screen. It is not.
The cameras focusing screen is internal and you view it by looking through the viewfinder, the best way to use is as a still camera, since trying to hold a nearly two pound camera at arms length introduces camera movement and usually blurry images
The LCD is there so you can check your exposure under difficult lighting conditions or when you are shooting video. When shooting video, you need a 3x loupe in order to use the LCD as a focusing point.
http://www.luminous-landscape.com/reviews/accessories/hoodloupe-3.shtml
And the best way to use such a loupe and shoot video is to buy a camera cage and follow focus device.
More on that
You could repair it yourself but only if you are skilled in such things.
Take it to a repair shop.