Facebook is blocked in different part of pakistan. So to use facebook in different area of pakistani you need to follow the following steps that will hep you to use youtube,facebook and twitter easily:
Search the term browsec proxy
Click the first item from the google search results and click to add extension, This will add extension in your browser and you will be able to use the facebook, twitter and youtube even its blocked in your reason.
Last step you need to follow in the image.