I've noticed when I do my inner eye detail, inner nose etc the day before I paint it looks good when I walk away but when I go to painting I sometimes notice it seems to have pulled or cracked away. Ever so little but still enough not to be smooth. And not always just sometimes. I mix equal parts and smooth in with alcohol on a paint brush. Is it something I'm doing wrong? Something I have to learn to live with? Should I mix clay in?