ok i have another question and please no rude comments. my 4 month old son was crying in his crib…

ok i have another question and please no rude comments. my 4 month old son was crying in his crib today and i didnt get him right away cuz i like for him to cry himself to sleep sometimes. then he started screaming cry i still didnt get him right away. then when i did get him and was holding him he fell asleep and then all of a sudden out of the blue his nose started to bleed. what could of caused it? it stopped and everything and he is asleep and doing good. we all get bloody noses here in the winter due to our house getting dry. could it be that his little nose got dry? he not dehydrated because he has tons of Tears and his nose was running