1) Is dried blood that comes out of ones nose najis? Dry meaning there is pleghm surrounding the blood however the phlegm hasn’t mixed with the blood.

2) Also, it it necessary for to check for najasah? E.g. one blows his nose is it necessary to investigate whether any blood has come out of his nose?

1) Dry blood is najes, but it you touch it with dry hands then your hands don’t become najes. Now if the blood is surrounded with moisture (like phlegm), then it makes the phlegm najes and so if you touch that phlegm your hands become najes.

2) No you do not have to check or investigate for Najasa.