So does anyone have a New Years Resolution to pop on those trainers and do some more exercise?! If they are new or haven't been worn for a while then they may rub a bit and give you an intermediate friction burn - otherwise known as a blister.
As always prevention is better than cure so as soon as you feel a hot spot (red superficial friction burn) then act immediately to stop it developing into a blister.
Gently clean the area that's rubbing against your shoes, pat dry thoroughly and apply a blister plaster such as Compeed. They're ultra thin so fit comfortably under most shoes, flex and stretch as you walk and stay put for a couple of days (even in the shower) keeping dirt and bugs out, allowing the area to heal and most importantly relieving discomfort instantly.
If it has blistered then don't be tempted to pop it as that will allow the bugs in and also the skin to rub on the nerve endings which will be sore. Just cover with a plaster and leave for a few days until it has healed.