I might be misunderstanding your post. Are you currently an RN? If your not already an RN you will have to get your RN before you can get into a nursing masters program. Most RN programs are a minimum of 2 years. Again maybe I am misunderstanding your post.
There are far more job opportunities if you have your RN compared to LPN. In the area that I live in most hospitals do not hire many LPN's. The pay is significantly higher with your RN but you have to keep in mind the responsibility is significantly higher with your RN, thus one of the reason RN's are paid so much more.
I always aspirate when giving and IM. If you get blood upon aspirating then you should pull the needle out and try again in another spot. Don't inject if you get blood because your are injecting into the circulatory system not the muscular system.