What should we do if blood falls on the Qur’an from a wound or a nosebleed, and we try to remove it with water but a trace of the blood remains, and the page of the Qur’an is slightly perforated?

A Muslim must preserve the Mus'haf (Quranic manuscript). If it is stained with blood or other impurities unintentionally, it is obligatory to remove and purify it with ritually pure water, even if that leads to its damage. If what stained it was impure, it should be removed with ritually pure water, or it may be burned if damaged. However, if the impurity is on the margin and did not touch the Quranic text, it should be purified with ritually pure water, or the impure part may be cut off.