Thanks for writing in.
I think you developed some allergy
to the hair gel you used. However, it is unlikely that the allergy could have lasted so long ( assuming you didnt use it again after you used it in class 12). If you have been using it regularly, I would suggest that you stop using it immediately.
Additionally, I would suggest that you have a diet rich in protein and biotin
. This means including plenty of pulses, non vegetarian items, eggs, green leafy fruits and vegetables and milk. Exercise for 30-40 minutes daily and reduce your stress
Additionally, I would suggest that you use Clofoam on your scalp
after washing your hair with a mild shampoo. This will help reduce the itching. Oiling your scalp regularly and following the above measures should help a lot.