From: Rabbi Moshe Sofer
To: Rabbi Tuviah Katz
The Chasam Sofer rules that the blessing 'al ha-milah' is recited even when returning solely to remove tzitzin that impede the priah. His key argument is that 'milah' means 'removal' of the orlah rather than 'cutting,' and since the Torah expanded the definition of orlah at Sinai to include the inner membrane removed by priah, priah is fully subsumed under the term 'milah.' This resolves subsidiary difficulties regarding the thirteen covenants, kareis, and the blessing formula.
Source: Shu"t Chasam Sofer YD §249