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If this was the first time that you have masturbated with insertion of foreign object in vagina, you could have ruptured the hymen that resulted in bleeding. If the bleeding is due to hymen rupture, it should stop within 24-48 hours. If there has been internal injury, bleeding can be prolonged. Look out for development of any other associated symptoms. Consider visiting your doctor/gynecologist for examination to look for the cause for the bleeding. Treatment as appropriate would be started to help you based on examination and test result. Drink plenty of water. Take adequate rest.
Take care.