Malik bin Anas (may Allah have mercy on him) says: The agreed-upon matter that has reached us is that there is no blood money for anything other than a bone-exposing wound in which the bone becomes visible. Blood money is only in the bone-exposing wound, and this is what the Prophet (peace and blessings be upon him) wrote in the letter to Amr bin Hazm (may Allah be pleased with him): "and he fixed its blood money at five camels."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الديات / 16209