Does the endoderm of the blastocyst later develop into the epidermis?
No, epidermis is developed from ectoderm.
Derivatives of 3 germ layers :
Here we can see the blastocyst has three germ layers : endoderm, mesoderm and ectoderm. Epidermis comes from ectoderm.
The endoderm later develops into digestive tract, liver, pancreas, thyroid gland and the lungs.