Is that the largest image you can get ? Larger will be easier. However, my 2 euros worth.
IMHO the bit to keep is the tongue. Free select
that ... and then invert the selection Select -> Invert.
Use Colors -> Auto -> White Balance on the selection Then kill the selection Select -> None
Then using a stock fuzzy brush (1) Reduce the brush size to suit the image (2) Reduce the opacity (3) Select a reddish colour from the top lip (4) and over-paint the bottom lip.
That should give something like this
As a long time PS user I will let you fix the eyes
IMHO the bit to keep is the tongue. Free select

Use Colors -> Auto -> White Balance on the selection Then kill the selection Select -> None
Then using a stock fuzzy brush (1) Reduce the brush size to suit the image (2) Reduce the opacity (3) Select a reddish colour from the top lip (4) and over-paint the bottom lip.
That should give something like this
As a long time PS user I will let you fix the eyes
