I have hypertrophic scars which are unsightly and slightly painful. How did this happen? (Photo)

My scars behind my ears were open for at least a month. The stitches were taken out after a week after a deep plane face and neck lift. As my scars healed they continued to look awful and now the scars are hypertrophic and tight and uncomfortable. They are now under my ear lobes and seem to be getting bigger.