Rash has appeared bilaterally behind ears. 36 yo male. Nkh of occurance. Small spot has also appeared on face. What should we do?

Rash behind ears. Since the most common cause of a rash behind the ears is seborrheic dermatitis (irritation of the skin due to excessive build up of natural oils), you could try over-the-counter 1% hydrcortisone cream for 3-4 days. If it doesn't help, then see a doctor. If it helps, continue until resolved.