Brief Answer:
I suggest you to use a ketoconazole based shampoo alternate days

Detailed Answer:
Hello and welcome to healthcaremagic

I have gone through your query and I have understood it.

Dandruff or seborrheic dermatitis is an important cause of scalp itching and increased hair shedding.

Since dandruff is bound to recur, therefore rather than using a regular shampoo, people with dandruff should use an antidandruff shampoo to keep dandruff under check.

If I was your treating doctor I would have asked you to use an antidandruff lotion/shampoo.
My choice for an antidandruff shampoo is 2% ketoconazole shampoo, thrice weekly OR even daily, for 2-4 weeks.
Nizoral is a ketoconazole based shampoo and is available OTC. It is marketed by XXXXXXX & XXXXXXX

However sometimes a shampoo alone seems insufficient. In such a case dermatologists choose to prescribe a topical steroid lotion (Mometasone lotion 0.1%), to be applied once daily at night, at the scalp skin for 2 weeks.
Topical steroid lotion is a prescription product and a dermatologist would normally prescribe it for resistant or difficult to treat dandruff.

The topical steroid lotion can be stopped once the dandruff is well controlled and thereafter the improvement can be sustained with just an anti-dandruff lotion/shampoo, twice weekly.

You may try the shampoo first, it that seems insufficient you may visit a dermatologist in your region for the needful

Hope this information helps
Regards

---