Are the side effects of chemo and radiation permanent, or will they eventually go away?

No: The side effects are divided into two parts generally for both radiation and chemotherapy. The short lived side effects: one will experience them during and shortly there after treatment. These side effects go away. The long term side effects: these are delayed and may stay for a long time or permanent.

Mostly go away: Side effects will usually improve and go away. However minor liveable changes may be permanent. Often patients may say they are not 100% back to normal but close. It depends on many factors and what has been exposed to how much radiation.