I think he seen something like a symbol that has to do with the Scarlet Letter!
Chillingworth's scrutiny of Dimmesdale is likened to a miner digging for hidden treasure. This extended metaphor highlights Chillingworth's relentless pursuit of uncovering Dimmesdale's secrets and his determination to expose his guilt.
Chillingworth catches Dimmesdale sleeping and thrusts aside the vestment to discover the letter A upon his chest. After this, there is no doubt in Chillingworth's mind that Dimmesdale's is Pearl's father.
Chillingworth's original wish to see justice done transforms into a desire for revenge as he becomes consumed by his hatred for Dimmesdale. Initially seeking justice for his wife's betrayal, Chillingworth's obsession leads him to seek vengeance and ultimately destroy Dimmesdale's life. His motives shift from a sense of righteousness to a thirst for personal gratification.
They saw the letter, A, scarred deeply into his chest, the same place where Hester wears her A.
Chillingworth catches Dimmesdale sleeping and thrusts aside the vestment to discover the letter A upon his chest. After this, there is no doubt in Chillingworth's mind that Dimmesdale's is Pearl's father.
Chillingworth's suspicions about Dimmesdale being Pearl's father are first aroused during a conversation where he observes Dimmesdale's physical and emotional reaction to Pearl and Hester. Dimmesdale's guilt and anguish become apparent, particularly when he sees Pearl and interacts with Hester, revealing a deeper connection to them. Additionally, Chillingworth notices the minister's deteriorating health and inner turmoil, which further convinces him that Dimmesdale harbors a secret related to Hester and Pearl.
Dimmesdale inflicts the scar on his chest as an act of penance for his hidden sin of adultery with Hester Prynne. By publicly revealing his secret guilt through the scarlet letter, he seeks to atone for his sins and find redemption. The scar becomes a visible symbol of his inner torment and desire for honesty and absolution.
Chillingworth emerges from the crowd at the event of the election and violently yells at both Hester and Dimmesdale. Dimmesdale finally admits his secret and reveals the letter "A" imprinted into his skin on his chest, and then dies, finally escaping Roger Chillingworth.
The major physical manifestation of Dimmesdale's guilt is the mark on his chest that is revealed before his death. This is his own personal "scarlet letter" that surfaces due to his guilt.
Dimmesdale climbs the scaffold to relieve the guilt and inner torment he feels for his affair with Hester Prynne. The source of his chest pain is believed to be physical manifestation of his emotional turmoil and guilt, rather than a specific medical condition.
In the marketplace, on the scaffold where Hester Prynne had previously stood with her baby as a punishment for her sin. This is where Dimmesdale finally confesses his own guilt and reveals the scarlet letter A on his chest.
Ailing Rev. Dimmesdale has a habit of clutching his chest over his heart, where he feels intense physical and emotional pain due to the guilt he carries from committing adultery with Hester Prynne.