我想問若已給法庭判社會服務令期間,再犯案,已認罪是否即時會入牢?急......

Normally, the court will give you discount in sentencing if you plead guilty at the first available opportunity. Changing pleads may do you harm. Try to obtain legal advice from a criminal lawyer.

Depending on the charge. If it is a serious charge, you will likely be sentenced to jail. Because you have already been dealt with leniently....the chance of a light sentence is unlikely.