Wow, I've been injecting Betaseron since 2003 and only use the back-side and belly. Once in a blue moon I use the legs. The arms are OUT. That hurts wayyyyy too much. I have a cream I got from the doc that really helps the red spots. Its called MOMETASONE FUROATE and it has to go on with a band-aid to seal it in. No band aid and the redness still comes on.
Now its important that the shots go in a certain depth. I'm concerned that you may be shooting too shallow. Do you use an autoinjector? If not you can get one for free by going to the MS Pathways web site. The depth on it is automatic at 12. If I inject without it and go too shallow...it hurts more. Also make sure the alcohol you use is completely dry before you let the needle go in. Some people get a really bad irritation from wet alcohol going in the shot.
Also.....rub rub rub the injection site for a good 45 seconds after the shot. This will smooth out the welt.
The redness however get your doc to write a script for the cream above. Just remember to use a band aid and seal in the cream over-nite.
Sometimes a warm wet compress before the shot helps soften the skin and can help....so can a cold compress. Try some different things and see if any help at all. Make sure you tell your doc the problems you are having.
Big Hugs to you