Both unilateral and bilateral contracts are enforceable in court. For example, a unilateral contract is enforceable when someone chooses to begin fulfilling the act demanded by the promisor. A bilateral contract is enforceable from the get-go; both parties are bound the promise.
Yes, scratching is a form of self harm. Try to tackle this problem while you can because it has the potential to get worse. I started out scratching and now I burn myself with a lighter and cut myself. It's a self-destructive way to deal with overwhelming mental/emotional pain.
1 It is best to avoid scratching when possible to avoid worsening of the condition and disruption of the skin that could lead to bacterial infection. 2  If itching persists with time or worsens, or is associated with skin lesions, consulting a health-care professional is advisable.