Hi Marco. On the lock pattern screen, you should see an option to tap in case you forget the pattern. You then have to enter your Google account information to unlock your phone.
You may need to try a factory reset, but it`ll erase all your data, so be careful:
1) Make sure phone is turned OFF
2) Hold both the Volume down button and the Power button
3) Volume down key to scroll to "Factory reset"
4) Press the Power key to start reset
5) Press the Volume down key to scroll to Yes - delete all user data
6) Press the Power key
7) When "Reboot system" now highlighted, press the Power key
Thank you it was so easy nd fast
mines just vibrates and i dont see none of those suggestions