How long 120mg. well, the half-life of methadone can be up to 59-hours, so after 2 and half days you would still have 60mg's in your system. But this doesn't take into account multiple doses.
A third type of lock is a security lock. This lock is like a typical password, to prevent someone other than the owner from using the phone. If activated accidentally, the user manual or carrier customer service can usually tell you the default code.
Reset/Change iPhone Restrictions Passcode. The only way to reset, change or remove the Restrictions passcode is to erase your device and set it up as new. By factory restoring your iPhone, you will lose all data on the device. Hopefully you've backup your precious iPhone photos, contacts, music, etc. previously.