Joi Ito explores the phenomena of cutting off fingers for punishment or protest, and why the Japanese don’t really understand it as a form of protest by Koreans.

For Japan:

..the origin of the Japanese the ritual of chopping off pinkies. In Japan, the ritual comes the importance of the left pinkie in the grip of a Japanese sword. Removing the left pinkie is literally disarming and was used to punish people in the past. This has been ritualized and continues to be used by small number of Yakuza and others in Japan as a form of punishment or taking responsibility.

For Korea:

… if I understand correctly, one of the most famous incidents was An Jung-geun, a legendary leader in the armed resistance against the Japanese occupation, chopping off parts of several of his fingers and writing "Korean Independence" in blood on the Korean national flag.

With that, I recommend South Koreans develop a form of protest that has more cross-cultural relevance and involves less pain.