How should I care for behind ear incisions after face and neck lift? They feel itchy and irritated.

I agree your plastic surgeon should give you specific instructions rather than following Internet advice.That said at 2 weeks your incisions are still healing.  My concern is that I did an proximal side may be irritating the incisions further.  Mild itching can be a sign of wound healing.You need to have your plastic surgeon examine your incisions and advise you accordingly.  Generally speaking I like the incisions to dry and avoid wet treatments.If at 3-4 weeks your incisions have closed but become red, raised, itchy, and the lumpy you may be developing hypertrophic scars.  Often topical applications of steroids can improve this process.  In some cases were hypertrophic scars are extreme the non-ablative 1540 fractional erbium laser can be helpful.  In rare cases steroid injections are used.  However it need not worry about these things at your early stage in recovery.

It is normal to have itchness around the scars as they heal. Using antibiotic cream may help but make sue to follow the instructions of your PS. I wouldnt be using peroxide at this stage but again you should see your PS for reassurance.

The post-op instructions should be always given by your operating Surgeon. Without pics- it is impossible to say. The quality of the neck lift is directly related to the position and length of the incision behind the ear. Often, when a large amount of skin from this area is removed - the neck will look much improved.