I don’t know what bites swollen a big piece of very hard causes include mosquito bites, bee bites, cryptococcus bites, tick bites and so on. 1. Mosquito bites: If it is a mosquito bite, you need to give 3% of the boric acid water cold compress treatment, external glycerine lotion, glucocorticoid ointment such as mometasone furoate. 2. Bee bite: after being bitten by a bee, usually first remove the tail pin, and then can be given a lot of soapy water to wash to treat. 3. Cryptococcus bites: For dermatitis caused by cryptococcus bites, hydrocortisone cream can be applied for treatment. 4. Tick bites: After being bitten by ticks, you need to remove the body of the insect intact and then apply mupirocin ointment, mometasone furoate and other medications to treat it. The appearance of do not know what bites swollen a large hard phenomenon please go to the hospital for examination, all drugs please follow the doctor’s instructions.