You have a Venipuncture Hematoma. (IV needle bruise, blood draw bruise) "Normal" No. Its not normal to stick sharp hollow objects through the vein wall to draw blood. It is normal for some bleeding to take place from a vein under the skin then the needle is removed. the larger the needle, the longer and more blood that seeps under the skin. Your "symptoms" fall with in nominal parameters for blood draw. Your vein bled out after the needle(s) were taken out. Instead of bleeding out to the surface of the skin the vein bled under the skin. The phlembotomist either tore the vein inserting or removing the needle or you are not well suited for the large gauge needles used for blood donation. A hemotoma (AKA bruising is a hemotoma - it basically means "blood under the skin") can leas to infection, however that is not a real risk factor here if you are in good enough health to donate blood. Use an ice pack - a pack of ice in something like a cotton t-shirt with a layer of the material between the plastic and your skin. Ideally the t-shirt material should be damp - this will conduct the cold without allowing freezing at your skin. Lay the ice pack on the affected area, let it sit about 20 minutes. Do this 3-5 times a day. The first 48 hours should see a small reduction in the size of the "blister" (as you called it) Coloring will take place, red to blue to purple, then after a few says yellow. If you develop a fever of 101 see a doctor - that would be a sign of infection. The the blister continues to get larger. See a doctor. If the bruise grows or covers more area after 48 hours, see a doctor. There will be pain, after 48 hours of cold you can treat with heat - cold will cause the blood vessels to shrink, preventing further bleeding. later on heat will increase blood flow which will speed up the removal of the "dead blood" in the skin. Pain will most likely be from the natural toxins that dead and dying cells give off (the blood in the "blister" is dying). Most likely you are not a good candidate for blood donations. If you do donate again explain to them what happened and ask them to use a smaller gauge needle. If it happens again then I strongly suggest you do not proceed with more donations. There are some folk who have thin vein walls. They do not do IV too well, their "thin walls" lead to excessive bleeding and in cases of excessive IV drug use "blowing" veins is very common - where due to the use of an needle the vein wall "explodes" after a few punctures. It is possible that you have "blown a vein" (Vein rupture) and this could be the real problem here.