As long as you don’t hit the sciatic nerve, there will not be any major problems. The general injection site for the buttocks is in the upper outer quarter of each side of the buttocks, which is the safest and less likely to damage the blood vessels and nerves. If the injection site is bruised, it may be caused by the needle of the syringe piercing the blood vessel. 2. sciatic nerve injury, which may lead to claudication and neuralgia. 3. local subcutaneous nodules, which may be caused by the accumulation of superficial drug injection under the skin. If there is no discomfort, it is usually not a big problem.