If you haven't created a reset disk before forgetting your password,you'd better to turn to a third-party software for help.Windows Password Key is a great choice.Steps about how to use it are as follows:
Step 1：Download a free demo version of Windows 8 Password Key on any PC you have access to.
Step 2：Run the downloaded file to install Windows 8 Password Key .
Step 3：Burn a boot-able CD/DVD or USB Flash Drive with Windows Password Key.
Step 4: Recover Windows 8 password with the burned CD/DVD or USB Flash Drive on your locked PC.
Any question please refer to http://www.lostwindowspassword.com/