One netizen pointed out on an online community that Taeyeon may have received some sort of touch-up on the corners of her lips. There is a plastic surgery procedure commonly referred to as the "smile lift" in which people, often females, re-align their upper and lower lips for an "upturned-lip" look.
The netizen used the following GIFs of Taeyeon before her latest music release:
Comparing them with GIFs from her "11:11" MV:
Opinions on the matter varied, and some stated that the idol mostly likely received botox injections to accentuate a more "upturned-lip" look rather than the full on cosmetic surgery procedure.
Comments ranged from, "Heol, if you're gonna do it, at least do it to look natural," "I feel like Taeyeon is very consistent with her touch-up procedures," "I was shocked at how different she looked in the MV," to "Whether she gets touched-up or not, what's it to you," "If you have time to find these things, go study some more," etc.
What do you think?