"90 Day Fiancé" star Kenny Niedermeier shared an update on how his daughter is doing amid their scary situation ... and it was most welcome.

Kenny says Hannah -- his daughter with fellow '90 Day' star Armando Niedermeier-Rubio -- underwent a procedure at the hospital and came out "very well."

He wrote on his Instagram story that more updates are coming -- and he thanked his followers for the outpouring of support during this terrifying time.

As you know, Hannah's suffering from a brain bleed and is being treated at an Arizona hospital.

Armando announced Wednesday that he recently noticed half his daughter's face had become "droopy" and half her body had lost its strength.

She was initially rushed to an ER in Mexico -- but ended up getting transferred to a Phoenix facility for better care.

Kenny is currently by their daughter's side, but Armando was turned away at the U.S.-Mexico border.

His immigration attorney had told us he's trying to get a spousal visa so he can be with his husband and daughter.

As of right now, doctors still don't know what caused Hannah's brain bleed, and it's unclear what procedure she just had -- but we're glad to hear it went well!