I have a question about waxing. I used to have really fine hairs on my neck (like peach fuzz). I made the mistake of bleaching them and that made the hair darker and thicker. I don’t want to bleach anymore as I am scared that it will only get worse. I was thinking about waxing the hair and wanted to see if you guys would recommed this. Will it make it grow back thicker as well? Also, if I do wax, should I use hot wax or waxing strips?
I think you should definitely avoid waxing it. Is it possible you're focusing on it too much and it's actually not as bad as you think? I think I would just leave it alone for a little while and see how I feel about it later...
Other people may have better input, but why don't you try a different brand of bleach and do a small patch test on your neck first? It might turn out that the new brand suits you better... And if it doesn't, at least you won't have applied it on your whole neck. I really don't think waxing your neck is a good idea, the skin there is too sensitive for that kind of thing, I think.
I highly doubt the bleach has made it thicker or darker; what would be the mechanism of action? Unless, you are using a desi bleach with steriods or some weird concoction like that.
How old are you and when did this start to happen? It is very common for women to find their fine, vellus hair thicken up regardless of what they do. Sometimes it is indicative of a hormonal imbalance like inspiron has mentioned but often it's also just a sensitivity to androgens.
A woman in her twenties, suddenly finds some thick chin hairs? Completely normal.
Whichever two of the above are the case, I am quite sure that if you start waxing it will just become worse. Since any kind of root removal is effectively causing small amounts of damage, the follicles need to repair and in androgen sensitive areas such as the face, chest etc, the follicles are usually strengthened instead of weakened. You are also opening up the door for ingrown hairs and hyperpigmentation.
Continue bleaching if it helps generally. Get a facial hair trimmer to keep the hair short if you want - this will NOT make the hairs worse than they may become naturally although it will give them blunt ends. Look into electrolysis to start removing the thicker hairs.
For bleach, I recommend boots smooth care hair lightener. Doesn't matter where in the world you are, I doubt you will find better that is safe.