Hi! I can't help you with the injection question because my daughter didn't have steroid injections. But she does have an upper lip hemangioma and her specialist had us do the oral steroids right off the bat. The meds did stop the hemangioma from growing almost immediately. I can show you some pictures of hers if you want.
I'm not sure whether or not that will help but at least you can see the progression on the oral steroids. Maybe you could ask the doctor what the other options are at this point if you are not happy with the results.