Penile irritation can be due to allergy or infection. To know exactly what ails you, consult a doctor and he will give you the cure for that. You can also go back here to ask other remedies once you're certain of your condition. Hope this helps!
Genital irritation should be taken seriously because it might be a sign of serious health conditions. Avoid having sex while you're not yet treated because you might aggravate the irritation or spread it to your partner.