well, I am sorry to hear that you feel that way, bear in mind that I have a son who has had many food challenges with a mixed response.
I am very aware of the distress that food challenges are to a child. I would expect that level of behavour or a decent amount of distress when going through a whole day of eating allergen. or flashpoints at home after the event.
Our children have a huge emotional burden with food allergies, and each reaction they remember colours their emotional well being for a considerable time after the reaction.
In fact having a family see a child go through a reaction, give them an epi, dash to hosptial is a huge emotional roller coaster. its like putting a whole family in a paper bag, shaking it and them tipping them out and watching how they cope.
So its no surprise that food challenges are distressing for small people, and its something that the pead immunologists really need to give more support in this area.
As for your childs reaction, it is good news that on this occasion it took a large amount of allergen to trigger a response.
But that was his reaction on that day and point in time. it still means that life with regard to sesame is still complete avoidance, as you are very well aware.
Factors that change reaction status from mild to anaphylaxis are.
recovering after a viral infection or illness.
amount ingested
poor asthma control
time of year, e.g environmental allergies (overfull 'allergy cup' iyswim)
and for adults,
alchohol
and time of month for woman.
Teen years and hormones are thought to change allergic status as well, but as yet no complete studies have been carried out,(as far as i know) but immunologists do hear of this peak. perhaps its a combination of hormones and risky behaviour.
So really you have epi pens, and as the docs havent told you otherwise you have a child with a potential for anaphylaxis.
what did the docs say about outgrowing? they must think its on the cards otherwise you wouldnt have been given a food challenge.
Personally we avoid may contains, due to reactions from them. It might be worth you asking that question on its own to other parents and allergic adults on this section.