If it was still Cornetto-shaped it can't have fully melted, or it would have all dribbled out of the cone.
The ingredients for a Classic Cornetto are:
Reconstituted skimmed MILK, sugar, WHEAT flour, vegetable oils (coconut, sunflower), glucose-fructose syrup, glucose syrup, HAZELNUT pieces (3%), butteroil (MILK), cream (MILK) (1.5%), fat reduced cocoa powder, emulsifiers (sunflower lecithin, mono- and di-glycerides of fatty acids, ammonium phosphatides), potato starch, whey solids (MILK), stabilisers (locust bean gum, guar gum, carrageenan), salt, skimmed MILK powder, caramelised sugar syrup, flavourings (contain MILK), WHEAT starch, MILK protein, EGG white. May contain: soy.
- most of those are preservatives so you'll probably be OK.