Is breathing in steam of boiling tap water while it is still on the stove dangerous? i did it for 10 min. i thought it would help sinus congestion. i asked this earlier, but should have been more specific. i regret and now worried about consequence

No worries: It depends on degree, meaning the amount of steam exposure, not temperature. Kitchen steam should always be about the same temperature. Every adult who has done major cooking in the kitchen has inhaled steam, so inhaling the kitchen air that contains steam, during typical cooking for 10 minutes, should be fine. In general, no worries. Death by steam is usually only in industrial accidents.

Caution: Steam can cause burns, but if you have no specific pain, it should be fine. An alternate method of clearing nasal congestion is to rinse nasal passages with saline to reduce post nasal drip. Upper respiratory infections typically resolve within two weeks.