When I was putting up my mezuza the parchment fell to the ground by accident. Does one have to fast for a fallen Mezuza parchment? Does one have to fast if the mezuza fell in the Mezuza case?
Magen Avraham (44:5) writes that there is a custom to fast if Tefillin fall on the floor, as there is if a Sefer Torah falls on the floor (R’Shlomo Zalman Auerbach rules that this is the case only if it falls from one’s hands and not if it falls by itself from an Oron Hakodesh).
However, mezuzah is not mentioned. Responsa Lev Chaim (3:131) rules explicitly that one need not fast in such a case.
Nonetheless, perhaps some personal introspection is in order, as well as donating money to tzedakka.
As far as making a brocha is concerned, if you are still involved in fixing it, a new brocha should not be made. However, if a mezuzah that falls later and needs to be refixed, Pischei Teshuvah (Yoreh De’ah 289:1) rules that a brocha should be made (as does Kitzur Shulchan Aruch 11:7 and Aruch Hashulchan 289:4; see however, Yabia Omer 3:Y.D. 17 who brings opinions that rule not to make a brocha).