Is that normal to develop hoarseness after Septorhinoplasty surgery?

I'd immediately seek the advice of an ENT specialist, you may need treatment, medical and phoniatric.

With septal surgery a tube has to be placed to protect your airway. Sometimes afterward there can be some hoarseness due to the endotracheal tube irritating your vocal cords. This typically improves within a few weeks.Good LuckStephen M. Davis, MD, FACSGreen Hills Plastic Surgery

If general anesthesia with an endotracheal tube was used during your surgery, it is not unusual in the days following the surgery to have a sore throat and a hoarse voice. It is somewhat unusual to have persistent hoarseness 3 weeks after your surgery. I would encourage you to follow up with your rhinoplasty surgeon so they can perform an evaluation and determine if there is anything that can be done to help your voice. Good luck.