baby poop 8 months old

Hey guys question about baby poop. My son is almost 8 months old. I started feeding him purées around 6 months but over the past week he actually started eating them twice a day (before that would just be a bite or two before he lost interest.) well now his poop is much harder than normal also he gets rashy when this happens. Has anyone delt with this? Is this normal or what can I do