If the phone has a data connection available, you can use it to recover the PIN via email. Simply enter your email that is attached to phone then you can find the PIN inside your email. If this is not the case for you, proceed to Recovery solution.
The sequence to enter Recovery Mode requires additional button which is another Volume button. Power off the phone and press Volume Down + Volume Up + Home + Power buttons all together until the service menu appears. When you're at the service menu, use the instructions from the previously discussed question.