Hello,
From the symptoms there are two possibilities: recurrence of the disease and secondly the diagnosis is wrong. First the person becomes symptomatic only after four to six weeks of infection, but on re-infection of recently cured person, symptoms appear within 24 hours. Continue to apply the ointment. Apply ice at the site to give you a soothing feel. Derbac M is a water based malathion, which kills the eggs of scabies. You can also try Crotamiton, which is non toxic, soothing a nd most commonly used. Also check for Psoraisis. Consult your Dermatologist for further advice and differentiation with psoriasis , scabies or dermatitis.
I hope it helps. Take care and regards.