Cat scab

My cat has this scab on her neck can anyone advise if anything bad I recently have got a kitten they do not fight and are in separate rooms at night I also have a feliway plug in 

Hello!  Cat bites can go surprisingly deep and have particular bacteria associated with them that cause surprisingly bad infections and abscesses, so if this is at all an option, a vet should be sought.  I hear you however that you don't think it to be possible in this case. Was there itching and scratching involved in this?  Fleas and allergies are both possibilities; it is easy for a scratch to nick the skin, enabling superficial bacteria from the nails or outer skin to move into the tissues, making a tiny scratch into something potentially infected.  It is also consistent with a new arrival to a household. I have seen superficial skin lesions after shaving, combing, fly bites, chemical bites and so on. I am viewing this on a phone screen so may turn later when I see the large picture if there are more ideas.  However, the lesion may be infected and it is a good idea to present it to a vet.