Is it normal for a scar to hurt 2 months after injury?

My daughter was bitten by a dog in December she had a 1 1/2 cm laceration about 1cm away from the side of her mouth, it required about 20 stitches to close. in all honesty, i was extremely freaked out when this happened and don't much of what the doctor said to expect. its been 2 months and my daughter said it is still very painful to touch and underneath the scar is a large lump which i just assumed was scar tissue but not i'm not so sure. she has an appointment with the plastic surgeon on Thursday but this is driving me crazy, any info would be greatly appreciated!!