The difference between salsa and picante sauce is that picante means that the sauce is hot so picante sauce is hot salsa.
While regular salsa may be mild or may also be hot.
It depends on the type of peppers that are used to make the salsa as to whether or not it will be hot or mild.
Picante sauce is usually a hotter version of the regular milder salsa.
Picante means that it's hot and not mild so that is really the only difference between picante sauce and salsa as they are both salsa but one is just hotter than the other.