Hi.. Can understand your concern.. As per your complain the ear lobe appearing blackish grey after piercing can be due to post inflammatory hyper pigmentation as when the pick is done soft tissues gets inflamed in that area.. The blood blister is formed due to injury to any minor blood vessel during prick leading to spilling of blood into soft tissues forming a small blister filled with blood..The blood blister mostly resolve by itself but can take a longer time to resolve.. The blackish brown discoloration if appears as a scum or a deposit it can be due to dust and debris accumulating in that area or can be due to corrosion product of the metal used in ear studs.. Your can use hydrogen peroxide to clean the deposit if it is there .. As you have punctured the blister you need not to worry and maintain proper cleanliness of the area and if you find some infection application of antiseptic cream like neosporin can be done. For discoloration hydroquinone or tretinoin based cream and steroid based cream can be used. Hope this information helps.. Thanks and regards.. Dr.Honey Nandwani Arora..