Is prostration of forgetfulness (sujud al-sahw) required for someone who raised their finger during prostration due to it being contaminated with blood and out of fear of soiling the carpet?

The obligation in prostration (sujud) is to prostrate on the forehead, according to the majority of scholars. Placing other prostrating limbs on the ground is not obligatory.

Prostrating on the hands does not invalidate it if a finger is raised, because prostrating on part of a limb is sufficient. Therefore, no defect occurred in prostrating on the hands, and no prostration of forgetfulness (sujud sahv) is required.

As for the blood on the finger, it is excused if it is minor, and there is no obligation to wash it. The prayer is valid with its presence.