Do not continue. Batteries and electronic components are not ordinary laundry and can create serious hazards when wet, heated or damaged.
Understanding this situation
Stop through safe controls where possible and follow appropriate safety guidance. Do not handle a hot, swollen or damaged battery, and do not charge it afterwards to check whether it survived.
A useful next step
Seek the relevant product and emergency advice if there is heat, smoke or damage. Tell the appliance service provider what was inside before inspection. Never restart the dryer to make the object easier to find.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.