There is no password recovery feature built in to Mycodo. However, if you have command line access to the system Mycodo is installed on, you can use the command line to create a new admin user, which will allow you to log in and change the password of any other user. To do this, execute the following command at the command line and follow the prompts:
~/Mycodo/env/bin/python ~/Mycodo/mycodo/scripts/create_admin_user.py