Touched is an event, not a condition, so you cant use it to check if a part is touching something else. Instead you can use GetTouchingParts() to get an array of parts that are touching the part you selected:
local parts = HumanoidRootPart:GetTouchingParts()
for i=1,parts do
if parts[i].Name == “Heat” and parts[i].Parent.Name == “Campfire” then
–put heat effect here
end
end