Recurring dry, itchy scalp patches with flaking and redness are commonly linked to seborrhoeic dermatitis, scalp psoriasis, eczema, or a fungal scalp infection. The worsening after using rosemary oil suggests that your scalp may have developed irritation or a contact allergy to the product. Almond oil may also leave the scalp greasy and trap flakes, which can sometimes prolong the condition. Selsun anti-dandruff shampoo (selenium sulphide) may reduce dandruff and fungal growth, but temporary relief usually means the underlying inflammation is still active. Using a medicated shampoo containing ketoconazole, coal tar, or salicylic acid 2 to 3 times weekly may help control the condition more effectively. In some cases, doctors prescribe mild steroid scalp lotions for short periods to reduce redness and itching. Avoid scratching, heavy oils, harsh hair products, and very hot water. If the patches spread, bleed, cause hair loss, or keep returning despite treatment, please consult a dermatologist for a proper diagnosis and long-term management plan.