^ she is totally wrong, there are many signs; red eyes, confusion, drowsiness/sleepiness, skin going pale to blue, loud snoring/gurgling, collapse to name just a few off the top of my head and as i mentioned in my earlier post, most of these are just confused with an extremely powerful nod but, unlike a nod, the person isn't high, they're dying. always take heroin around people if you can and let someone know what you're taking if you do, carry naloxone/narcan on yourself whenever you use so that you can administer to someone or have someone administer to you if you're the one ODing (and once again, if you're with people let them know you have narcan on you).
stay safe