Lip stretching after lip lift. 5 weeks post-op.

I have seen comments regarding upper lip "stretching" to help with short upper lips. I had too much removed when I had a lip lift- 8mm removed. I would love to gain some mm. I am now 5 weeks post surgery and have not seen any signs of "dropping". What are the "lip stretching exercises" I have read about on Real Self? When can I start these exercises?