about 2-6 weeks after the vaccination, a blemish appear at the site of the vaccination. It can grow into a circle up to 7mm in diameter. It can be painful and bruised for a few days, but will eventually heal. It usually leaves a small scar.
Rarely, some people may have a more severe skin reaction. This should heal within a few weeks.
If you are worried that you or your child's skin reaction is abnormal or that the spot may have become infected, contact your GP.