Neem oil can certainly help get rid of scabies but there are ultimately better choices that will work faster and heal your skin faster. Neem oil is good for soothing the damaged skin, reducing redness, reducing inflammation and helping prevent secondary skin infections. Much like scabies sulfur treatments it is something that is far less damaging to your skin than the use of pesticide based scabies treatments.
If you have used pesticide based treatments and they failed you should certainly try using sulfur scabies treatments or neem oil treatments as there have been reported cases of scabies being resistant to permethrin based pesticides. Much like sulfur scabies treatments, neem oil has been used for centuries to aid in the treatment of scabies mites.
Using natural treatments to kill scabies is preferred as they can penetrate the skin deep enough to kill both scabies and eggs. Pesticide based scabies treatments can cause further damage to the skin and even make it more itchier following the first few weeks after treatment.
Dermatitis is very likely in post scabies as your skin is very damaged and your immune sytem is working overtime. Using sulfur scabies treatments or neem will help prevent any post scabies Dermatitis and secondary skin infections which is why they are preferred.