It is advisable to use a fermented soybean cake.
Scallion white (Allii fistulosi Bulbus) and Douchi (Fermented Soybean, Dan Chi) in equal parts.
Pound the above two ingredients together into a cake, apply it to cover the affected area, leaving the sore open to vent the pathogenic qi.
Another prescription:
Bark naturally shedding from the trunk of the locust tree (Sophorae Flavescentis Cortex), ash from green bark, eggshells of *Nycticeius chinensis* (Voluta plicatella shell, Fu Chu Er Ji Zi Qiao) calcined on tiles, Calomelas (Qing Fen).
Grind the above ingredients into a fine powder, mix well, and apply topically.
Yet another prescription:
Grind Yin Guo Zi (Pottery shard from a silver pot, or specifically referring to a local herb name often identified as *Ecliptae Herba* or similar in folk contexts, but literally "Silver Pot Child/Seed") into a fine powder for topical application; this is extremely effective. Mixing with egg white (Ji Zi Bai) is also acceptable.
Jing Mi Cao (Caryopteris Incanae Herba, Gu Jing Cao) selected for purity, Chan Ke (Periostracum Cicadae, Chan Qiao) each 1 liang, Cang Zhu (Atractylodis Rhizoma, Cang Zhu) 5 liang.
Grind the above ingredients into powder. Take 1 qian per dose, mixed with water and swallowed. Before taking the medicine, still prick the ding (carbuncle/furuncle) with a needle to drain the blood/toxins, then wash with juice from mulberry wood ash for immediate effect.
I, Xu Wenli, though untalented, was invited by the virtuous Prefect to seek medical advice. It happened that Eunuch Wang of Xin'an discussed back lesions. I successively cited various schools' treatment methods, which coincidentally met his expectations. Thus, I was commissioned to compile, classify, and correct them into a single book, named *Wei Ji Bao Shu* (Precious Book for Guarding and Aiding Life). May later readers not mock my ignorance and presumption. Recorded by Xu Wenli.