i just has my 1st injection 3 days ago. my friend gave it to me in the right butt cheek up high near the hip. the next day it was really sore and swollen and was red. today it is not nearly as sore and the swelling has gone down some but it is still red and it is warm to the touch. also, the area under the skin where the needle went in is hard to the touch almost like something is under my skin. what is wrong. will it go away without seeing a doctor and getting some meds and if so how long will it take. how serious is this.