Scars of Ink

Harry Potter, the boy who seemed to embody both defiance and vulnerability in equal measure, sat amidst a sea of his fellow classmates, his hands trembling as he stirred the noxious brew. Snape's lip curled in disdain as he observed the boy's nervous movements, the air around him practically crackling with tension.
Potter's presence always seemed to ignite a tempest within him, a constant reminder of unfinished business, of debts unpaid. But today, there was something different, something that made Snape's blood run cold—a flash of crimson peeking out from beneath the sleeve of Potter's robes
Or:
Snape sees the damage from Umbridge and is left with thoughts.