وَإِذَا رَمِدَ وَأُمِرَ أَنْ لَا يَغْسِلَ عَيْنَهُ ... وَضَرَّهُ نَزْعُهُ جَازَ لَهُ الْمَسْحُ، وَإِنْ ضَرَّهُ الْمَسْحُ تَرَكَهُ
The same principle applies to medically protected areas such as an injured eye or a broken nail covered with medicine where removal would harm. If wiping the covering itself would also cause harm, the text allows the wipe to be omitted. The concession follows actual ability and harm.