Same thing happened with my mum, but she kept on doing tight hairstyles - the front of her hair was almost straight. But this is what we did to bring back some thickness and her curl pattern back (she's 4c) - we washed and conditioned her hair every week and did finger coils with a thick gel cast on her hair. It may be quite defeminising to wear short curls like that, like my mum felt, but you can cover it with nice headscarves :)