4 weeks post facelift and bi lateral blephs: stabbing pains behind right ear and healing worries. (Photos)

It appears that you may have some superficial wound breakdown behind your left ear (and "stabbing pains" may be related to suture erosions - dissolving sutures can generally be present for 2-3 months), which may respond to a minor bedside debridement (clean-up) with your surgeon, and (at least) antibiotic ointment 2-3x/day. Irregular sensations also may be due to tiny skin nerve interruptions and subsequent irritation during the healing process, and are generally self-limited (spontaneously improving) issues, although it may take up to 6 months or longer to "normalize".  Stay in touch with your surgeon, who will know more than anyone what was done and how to care for these minor issues.

The pain behind the right ear does not seem to be associated with infection and is more likely to be related to some of the dissolvable stitches that are holding the tension. It is most likely to settle on its own.
On the right side, there appears to be a small wound breakdown which will probably leave a slightly wider scar. It is a problem that your surgeon would be able to address under local anaesthetic when the area has settled better. Keeping the area clean is important to avoid infection.
Although the wounds appear worrying at this point you will be amazed how much natural improvement happens over the first 6 months from the surgery. Stay positive and work with your surgeon to get the best result from your surgery.