NEW TEAT?

so my baby girl is 8 months old. She’s a premie baby so was discharged with a medium flow teat since day one.

I have noticed recently when she’s drinking her teat is collapsing in on itself so I have to get it out for her to be able to continue drinking milk.

Do I need to move her to a larger teat?

She is currently on NUK bottles

Any advice would be greatly appreciated :) xx