tobradex used a while back, now get pain

Hello,
Mom had some redness in her eye last October
and the optometrist prescribed tobradrex.
She took the recommended dose for 3 days.

Since then, she has occasional pain in the
eye which goes away quickly, but is this
something to be concerned about??

She occasionally also feels an itch in the
eye. But again, it goes away quickly.

Could an earlier use of tobradex for eye
infection treatment cause this occasional
pain and is there any known solution?

Thank you very much!