Safe to put honeycomb in tea?
Honeycombs are the bees’ “storage containers”, i.e. cells out of beeswax filled with honey. Beeswax melts at around 62-64 C (144-147 F), so its no surprise that the combs melted in hot tea. 

From a food-safety perspective, beeswax is totally harmless. The (purified) wax “cera alba” is used in foods, medicine (even in bone surgery!) and cosmetics. The European Union has not given a maximum allowed daily intake. 

As you are using honeycomb (as opposed to brood cells), the amount of “dirt” or debris that might be in the combs is minimal, certainly nothing worth worrying about. 

In short, enjoy your tea! If you dislike the texture, e.g. the small hardening wax chips floating on the cooling tea, skim them off.