Question: [Sunday 12th Menachem Av, 5780]
My Batim are Dakos and have some dents on the bottom of the Bayis Shel Yad and Shel Rosh seemingly due to wear and tear and rubbed off skin. Are they still Kosher?
Yes. Your Batim remain Kosher so long as their square shape is retained and there are no actual holes.
Sources: See Admur 33:1; Keses Hasofer 24; Maharam Shick 19; Piskeiy Teshuvos 33:1