I’d use polysporin in my nose, it cleared mine up. I had the flu and I had irritated my
Nose and it was raw and red.

Seborrheic dermatitis can worsen due to factors like stress, fatigue, changes in weather (especially cold and dry conditions), and certain skin care products that irritate the skin. Additionally, hormonal changes and an overgrowth of the yeast Malassezia can also trigger flare-ups.
WebMD Wikipedia
Common Triggers for Seborrheic Dermatitis
Environmental Factors
Cold Weather: Symptoms often worsen in cold, dry conditions. Low humidity can lead to dry skin, exacerbating the condition.
Heat and Humidity: High temperatures and humidity can also trigger flare-ups for some individuals.
Lifestyle Factors
Stress: Increased stress levels can lead to flare-ups. Stress may weaken the immune response, making it harder for the body to manage the condition.
Fatigue: Lack of sleep or excessive fatigue can trigger symptoms.
Skin Care Products
Harsh Chemicals: Products containing alcohol or strong fragrances can irritate the skin and worsen symptoms.
Inadequate Moisturization: Not using a moisturizer after washing can lead to dryness and irritation.
Dietary Influences
Western Diet: Diets high in processed foods may be linked to increased symptoms. Incorporating more fruits and vegetables may help reduce flare-ups.
Medical Conditions
Neurological Disorders: Conditions like Parkinson's disease can increase the risk of seborrheic dermatitis.
Immune System Issues: A compromised immune system, such as in HIV or after organ transplants, can worsen symptoms.
Hormonal Changes
Hormonal Fluctuations: Changes in hormone levels, particularly during puberty or menstrual cycles, may trigger symptoms.
Identifying and managing these triggers can help control seborrheic dermatitis and reduce flare-ups.