Simple Question on MESSENGER ,on my Mobil?

[AC Question]

I got a new smart phone a LG G, My gf had a facebook a long time so i wanted to simply put MESSENGER on phone and use it to chat with her. I let my buddy switch accounts to check his facebook thru my MESSENGER so when he logged me out for first time i cant seem to figure how u simply find your own password i forgot for my personal mobil MESSENGER ACCOUNT a great program with no reset or lost passwords option i guessed 1900x but no luck what who n where do i email or call to find get a new password to simply log switch bk to my mobil MESSENGER ACCOUNT..i thought i was smart not stuck on a small but huge problem??? Please give any simple advice no i never made a Facebook why when i ONLY want to talk to my lover n i will someday but loved i could use MESSENGER to message with her n her Facebook had i really seen her fb activity i woulda broke up long ago...