I just ate a slice of cheese & i can feel my fingers swell up is that lacto intorence or something else?

Something else: Lactose intolerance generally presents as abdominal bloating and diarrhea. It would be unusual for it to present as finger swelling. A more likely culprit is increased salt intake or heat. If you have swelling in your ankles, shortness of breath or have a heart condition, this could point toward something more serious. In that case i would recommend seeing your physician.

Unlikely Lactose Int: The typical signs of lactose intolerance are abdominal bloating and cramping along with diarrhea, gas and sometimes nausea within 2 hours of ingestion of milk products. Unfortunately, without more information it's difficult to assess the symptom you describe, however it seems unlikely to be related to lactose intolerance.