Midras Keluaran 21:25: Mekhilta DeRabbi Yishmael & Mekhilta DeRabbi Shimon Ben Yochai

(Exodus 21:25) "A burn for a burn": If you say (the meaning is that he burned him and spilled his blood, this is already subsumed in "a wound for a wound." If you say that he made a welt, this is already subsumed in "a welt for a welt." How, then, is "a burn for a burn" to be understood? As his burning him on his nail or on the sole of his foot without leaving an impression, lading him with stones and causing him suffering thereby, placing snow on his head and making him cold — in which instances he compensates him for his suffering. But if he were frail, indulged, and pampered, how much more so is his "suffering" allotment to be doubled. This is the (type of) suffering intended in "a burn for a burn."

Burn for burn - if with wound it was already said, but if even though there is no wound [inflicted], such as he hit him with a [towel?] or a nail on his nail, on a place that does not make a wound, from here you say that one who diminishes the limb of his fellow, he pays five things: damages, and pain, and idleness, and healing, and shame. Damages and pain are spoken of here. Idleness and healing [are spoken of] above. And shame in another place, as it is written (Deut. 25:11) "and she stretches her hand and seizes him by his genitals [lit. shames]." Damages - we assess him: how much is he worth complete, and how much he is worth after he made him lose a limb. Pain - we appraise how much a person would want that would be given to him to have his hand cut with a narcotic or not cut at all, [cut]with a slaughtering knife. Idleness - we see him as if he is a guard. Healing - we appraise in how many days he will heal, and how many are needed. And shame - All goes according to who shames and who is shamed. And if he did not make him lose a limb, he is exempt from damages; and if there is no pain, he is exempt of [paying for] pain; and if there is no idleness, he is exempt of [paying for] idleness; and if there is no healing he is exempt of [paying for] healing; and if there is no shame, he is exempt of [paying for] shame.