I made a ceramic clay sculpture of a Gazelle for my sculpture class, but when I went to fire it in the oven one of the cheekbones fell off and some other pieces cracked and fell off, nothing serious but I'd like to know how I could reform the cheek and fill in the cracks so it can be a smooth, seem-less surface allover, I tried using more clay but it just cracked and fell of when it dried, should I try caulking or something else? Thanks!