Hello, and thanks for writing in.
The biggest concerns would be potential stomach and intestinal upset, which may include vomiting and diarrhea. In a severe case, the pancreas may get inflamed (pancreatitis) from ingestion of fats in the soap. I would watch Luca closely over the next 1-2 days for vomiting, diarrhea, lack of appetite, lethargy, acting uncomfortable. If he exhibits any of these symptoms, I would recommend getting him into a veterinarian for appropriate treatment.
I hope this helps.