Hello,
Thanks for posting your query at DoctorSpring.com. I can understand your concern.
Hair straightening of any kind can result in physical damage to the hair. This results in hair thinning and hair fall.
I would recommend you to not get done such hair straightening again.
You can take supplements of biotin which is the vitamin good for hair growth. Also application of minoxidil lotion stimulates hair growth.
It's also advisable to see if there is any other cause of hair thinning like female pattern baldness which is seen with widening of central parting which occurs due to raised levels of androgens.
Hope this helps, please feel free to discuss further.
Take care