I take an inframuscular injection every week, and I've accidentally been doing it at the same injection site.?

And now I think something may be wrong. I didn't realize I was suppose to alternate injection sites, and instead I've been taking it at the same leg. Now, the mediciene doesn't seem to be moving in my leg (where i've injected it. Its just localized at the injection site. I don't know what this means. I mean, it only very slightly hurts when I apply pressure to it. Should i wait it out and expect to disperse over time, is this normal, or should i go to a doctor?