I'm surprised nobody mentioned this yet:
There are many different alcohols: methyl, ethyl and isopropyl to name but a few.
Working with Methyl alcohol can cause blindness!!! A Google search gave me that denatured alcohol consists of 90% Ethyl, 5% Methyl and 5% Isoproyl.
Another google search gives this on methyl :
"Toxic by inhalation, ingestion or skin absorption. May be a reproductive hazard. Ingestion may be fatal. Risk of very serious, irreversible damage if swallowed. Exposure may cause eye, kidney, heart and liver damage. Chronic or substantial acute exposure may cause serious eye damage, including blindness. Irritant. Narcotic. UK exposure limits: long-term 200 ppm, short term 250 ppm."
R11 Highly flammable.
R23 Toxic by inhalation.
R24 Toxic in contact with skin.
R25 Toxic if swallowed.
R39 Danger of very serious irreversible effects. (This one is pretty serious, don't ya think?)
S7 Keep container tightly closed.
S16 Keep away from sources of ignition. (LOL)
S24 Avoid contact with skin.
S36 Wear suitable protective clothing. (Nope your pata 1 shirt is not protective clothing)
S37 Wear suitable gloves. (Nope your gloves are not suitable)
S45 In case of accident or if you feel unwell, seek medical advice immediately. MAYBE THAT'S GOOD ADVICE TO DO RIGHT NOW! (show the label whenever possible.)
Searching for denatured alcohol gave me :
"EYES: Irritant. Redness and itching may result from exposure to vapors or liquid. (And while cooking you produce a lot of alcohol vapours)
EYES: Rinse with plenty of water for at least 15 minutes. Get professional medical assistance. (Yet another good advise)
Safety glasses are considered minimum (!) protection. Goggles or face shield may be necessary depending on quantity of material and conditions of use."
Another Google find a bit lower down on the first page :
R11 See above
R20 Harmful by inhalation.
R21 Harmful in contact with skin.
R22 Harmful if swallowed.
R36 Causes severe burns.
R37 Irritating to respiratory system.
R38 Irritating to skin.
R40 Limited evidence of a carcinogenic effect.
S7 See above
S16 See above
S24 See above
S25 Avoid contact with eyes. (Hmmmm good idea)
S36 See above
S37 See above
S39 Wear eye / face protection. (Hmmm good idea)
S45 See above
So I'm pretty sure that the vapours you're producing because you're burning alcohol cause your eyes to hurt. CALL YOUR DOCTOR TODAY! Just in case. Working with alcohol in a lab you have to work in an exhaust booth!
Now you shouldn't worry or stop using alcohol. The tiny exposure you get from cooking on alcohol every now and again won't do you much harm, but next time do not use it inside the tent anymore. Apparently the ventilation isn't enough.
Call your doctor! Just in case.