I was on 140mg of clexane forte for a blood clot and the first one was the worst. It stung like a [insert rude word]. I was told what ever you do don't rub them as it will cause bruising, to be honest I found that I only ever bruised when I hit a vein with the needle. After a few days though I didn't notice the stinging as much, and after 6 weeks I barely noticed it at all. I held my hand over the site with a bit of pressure for a few seconds and that helped a bit (I image this could cause bruising too though)

I hope it gets and keeps you pregnant