Blood blisters on the tongue may be caused by trauma, hemangioma or thrombocytopenia. 1. Trauma: people accidentally bite the tongue when chewing; eating hard food such as melon seeds, chewing sugar cane and tongue friction; eating hot food caused tongue burns and other traumatic reasons, can lead to blood blisters on the tongue. 2. Hemangioma: when hemangioma occurs on the tongue, a dark red bump similar to blood blisters may appear on the tongue surface, and patients mistakenly describe hemangioma as blood blisters because they are not clear about the nature of the bump. 3. Thrombocytopenia: when there is a pathological reduction of platelets in the blood, purpuric foci similar to blood blisters may appear on the buccal mucosa and tongue mucosa. Once blood blisters are found on the tongue, it is recommended to actively seek medical attention to clarify the etiology.