I put undiluted savlon all over my face and left it overnight, now my face is red and it burns horribly to the point where i cannot touch it.

Skin injury: You have developed Chemical dermatitis due to excess of Savlon.It is like a bad sun burn and will likely behave like one. So you will have to give it time to heal over the next several days(may take 7 to10 days). If you have a doctor whom you go for check ups, let him/her check your face for any infection during the time of healing. You will also benefit from pain medicine like Tylenol 2 tablets.