Piotr - I'm going to suggest you push your dr. to send you to an ENT for a biopsy. Now admittedly scratching the top of your tongue could very easily cause bleeding, and usually the top of the tongue is full of taste buds that can swell - particularly if you have some kind of an infection - or chronic irritation (which can be caused by smoking) So possibly with swollen buds, and scratching them blood is possible. However, you need to rule out anything life threatening (an underlying tumor?) SO again I stress, you need to push your dr. to send you to an ENT (Ear nose and throat specialist - one that deals with oral cancer) and have him or her look at the area. Most importantly YOU NEED TO QUIT SMOKING!!!!! hugs and welcome again.