Hi Steff
I find that I don't usally get a mark but sometimes I do find a yellow bruise a few days later! I guess it depends on if you nick a tiny blood vessel or not.
As long as the arrow in the pen window appears (and it is sometimes off centre -again, don't worry) you have received your dose. Also you someitmes get a few drips of the fluid as you reset the pen after the shot- again, this is normal.
How are you getting on- sickness gone yet? xxx