According to my Morin Catalog of Belgian coins the small head coins have the name of the engraver near the edge. The large head coins have the name near the cut of the neck. The large head variety is rare!
The 1886 small head occurs in two varieties, with or without dot after the F (from Francs'Frank) with the variety with dot the rarer one.
A picture of the entire obverse (heads side) would help!