First of all, physically wash away the contaminant:

• Blood in a cut or puncture: encourage the wound to bleed outwards by squeezing or pressing. Then wash it thoroughly with soap and water.
• Blood on the skin where there's no cut: wash with soap and water.
• Blood in the eyes: rinse while open with tap water and saline.
• Blood in the mouth: spit out, rinse with water and spit out again.

Then follow the Hepatitis B protocol, seek medical advice and report the accident.