dear, first of all thanks to writing to HCM, since u used small needle and the quantity injected was bit too much , its quite possible that drug didnot reach the muscular tissue and it got clumped in fatty tissue of ur hip.as already its 6 days which is usual time for a injection abscess to be developed . steroid on their own may produce severe itching and if the swelling is pain ful i will recommend u to visit a surgeon asap. benadryl is okay for itching but swelling wont subside with that. for swelling u must use either thrombophob ointment or use of ice pack may be help ful. if its associated with fever i request u to go to ER asap. thanks revert back for follow up.