Picked this one as I have never dealt with a stain of this size or type before.
Wanted to see how far Photoshop could deal with this automatically (and mre importantly if I could handle the challenge!)
Examined the channels in RGB - obvious damage in Green and Blue (did not see anything in the Red !) so set about doing my best to fix them concentrating on the face.
1. Green channel blends with Red using a couple of different blending modes.
2 Similar blending with the Blue channel
After these actions the main reddish staining had been eliminated from the face but a small amount light yellow staining appeared, running from the centre of the forehead down through the nose
and into the neck area. There were also remenants of red staining showing in left hand background and top centre of picture extending into the hair and forehead. Perhaps I should have tried a little
harder with blending but I reasoned that the rest should easily be corrected manually (I think the term is 'turned chicken')
3. Retouch yellow staining using colour replacement tool and a little cloning. Little work to clean staining on teeth.
4 Mask the red stain in hair and used curves to get a close match to rest of picture
5 Repair corners and decided that the logo should be either cloned out or repaired choose the latter although it is unlikely to represent what was originally there!
6. Finally applied curves layer mask to skin tones tones
Decided to stop there and not retouch the yellow remaining in the chin and neck - reasoned that this could be just reflection from the yellow garment - or maybe I had just had enough.