I have tried putting salt (even until blood came out) but the
healing duration still remains the same. So I guess salt does not
works for me and it is something to do with my body rather than the
wound.
I think not only should drink more water (at least 8 big glasses
daily) and eat more green leafly vegetable, one should refrain from
taking heated-water bath. Use tap water instead as its temperature
should be cool enough to cool the body. If you love eating stuff
while it is hot (eg. hot soup while it is steaming), then try not
to, as it is bad for the wall of your mouth as it kills a lot of
good cell.
As what browniebaobao adviced, get more sleep and refrain from
heaty food. If possible, sweat a bit everyday to PAI DU.
Try take the above advise for a month or 2 and see if it works for
you. If it does, then share it with others.