Diagnosed TE after having the contraceptive implant fitted. 11 month shed - implant now removed, when should I see improvement?

TE can last 8-12 months. I suggest seeing a hair loss expert to evaluate and go over your condition and provide you information about your best treatment options. There are great non-invasive options like PRP/progesterone and/or hair transplantation. See an expert. Best, Dr. Emer

Generally once the cause of hair loss has been eliminated hair can start to regrow.  Note that for women in particular other stressors may also be contributing so you will want to see a hair regrowth specialist for a comprehensive diagnosis.

A telogen effluvium can last 8-12 months. Women often have more than 1 reason for their hair loss, so don't assume it's just a telogen effluvium (TE).  Be sure other causes have been completely ruled out by your dermatologist.  

It might take up to a year to see the results on your TE from when you stop the contraceptive.  The timing is not absolute