Is this swelling or seroma after face and neck lift? (Photos)

Looking at the photo you submitted , it is hard to state if this is swelling or seroma. If you apply gentle pressure to the suspected area and that area feels as a waterbed or filled with fluid as opposed to swelling , it is most likely a seroma.  You need to schedule an appointment with your board certified plastic surgeon that performed the procedure immediately if you feel this might be a seroma. A Seroma is typically easy to manage and resolved by your plastic surgeon.  

You have a scar under the chin and therefore have had a submental approach to correcting the neck. This generally causes more swelling . However, it is still important to consult your surgeon in case this is a seroma which is easily detectable on examination.

Thank you for your question and pictures.  Please return to your surgeon to have a follow up appointment so they can examine you and detect to see whether its just swelling.  All The Best