Dermatologists: what do molluscum bleed?

Do you mean: "why" do molluscum bleed? If so then like any lesion on the skin, if it is scratched off the resultant injury may bleed. However, molluscum generally don't spontaneously bleed (i.e. On their own).

Molluscum: Bleeding may occur if the lesions become scratched or caught on clothing for example. See a dermatologist for treatment options.