1)
How can we reconcile this Pasuk and Pasuk 13 with the fact that Bil'am left with the dignitaries of Balak with the express intention of cursing Yisrael?
1.
Rashi (in 22:20): He hoped to entice Hashem to consent to let him curse.
2.
Ramban: His initial reaction was to do only what Hashem commanded him, but he later changed his mind and accompanied the emissaries with the intention of cursing Yisrael, until the angel warned him to desist.