Jowl appearing on one side only after lower facelift. How could this have happenen?

If the "jowl" is above the jaw line, it may actually be a sliding buccal fat pad. Thee appear as fullness in the lower face above the jaw line. Different than a recurrent jowl

Assymetries and irregularities are not unusual after facelift surgery.  These risks are clearly explained to patients and should be understand as a possible undesireable result which can be routinely corrected.Tightening of the neck skin requires a direct approach to the neck. Options include the Precision Tx internal laser to improve the wringling, tighten the neck and reduce jowls. Liposuction of the submental region and jowls will tighten and smooth these areas. Botox or excision of Platysma muscle bands will improve subcutaneous banding. A neck lift will tighten neck skin; some patients are dissapointed due to recurrence of the fine wrinkles under the chin.Please consult in person with an experienced Board Certified Plastic Surgeon prior to making treatment decisions.

You are still very early in the recovery process and you need to give yourself more time to see the final results.  Keep follow up with your plastic surgeon.

Swelling can improve for several weeks after surgery, so do not feel like it is a lost cause. Visit often with your surgeon during this time to make sure there is nothing he/she would like to address while there is still a chance to affect the final outcome. 

At two weeks postop, your face is healing still from your facelift. What you are seeing is not your final result. You may have some persistent swelling. Give yourself time to heal and you can discuss your concerns with your surgeon.