Do you get bad cramps monthly? Irregular periods? Any signs of a hormonal imbalance?
I used to get cold sores EVERY MONTH around the time of my period & what stopped them was going on the pill. I read it as a tip off from some farmers medicine website that the imbalance of the hormone prostaglandin can cause cold sores in woman.
And about the cold sores vs allergy part. Well let's pick that apart. Cold sores are the product of something triggering the virus, the HSV-2 virus lies dormant in the deep nerve endings until something triggers it. Common triggers are sunlight/sunburn, spicy foods, stress, getting your period, the use of corticosteroids, sickness, etc. Basically anything that lowers your immune system can cause a cold sore, hence the name, cold sore. Now let's look at allergies.. allergies are caused from the overreaction of the immune system which can be triggered by just about everything. Eczema is an overreaction of the immune system, and it usually starts off as itchy, then bumpy, then rough feeling(like sandpaper), then swells, and then feels funny when you itch it. So cold sores have nothing to do with allergies whatsoever, sorry.
My mom's done this before, but what you did by using the steroid cream was just about the worst thing you could do for it. Your harvesting a virus by lowering your immune system response. With cold sores you should be trying to INCREASE your immune levels by drinking lots of OJ, taking vitamin C & lysine supplements, and possibly using an antiviral cream or pill(if you can tolerate it). If you are prone to cold sores, you should consider going on the pill or taking immune system supplements. Some helpful treatments while having a cold sore is to split a Vitamin E capsule & put it on the cold sore several times a day, use an antiviral cream(HIGHLY recommend Denavir), use a burst of oral Valtrex, drink tons of OJ, etc. Some tips for preventing cold sores.. know your triggers. If you do ANYTHING, ANYTHING at all that could cause a cold sore(tanning, prolonged sun exposure, illness, etc), put the antiviral cream all over your lips & nose. No it won't hurt you to take it as a precautionary measure.
Generally, eczema doesn't cause "painful, burning, itching" that cold sores do. You can tell by looking at the cold sores the difference, cold sores will have like clear bubbles almost that crust up and fall off, eczema doesn't crust up really, it just oozes & weeps, then dries and is like peeling off a layer of skin.
So my point is, it's not an allergy from what it sounds like. Your doctor is right.. the antiviral cream won't do 2 much if you start it AFTER the cold sore has erupted, maybe shorten if by a month or 2. Believe me.. I have had cold sores and eczema all my life & the 2 are very, very distinct conditions which are treated in 2 completely separate ways. And whatever you do, don't use the steroid cream again unless you want an entire face full of cold sores..
BTW.. are your glands swollen at all?

OK answers your reply to my origional post..... I said in that one that it was NOT cold sores and that it was a reaction to the mangos. It was just like when I got poison ivy. I would not have taken steroids for them because I took a valtrex immediately and it did not help at all. Valtrex worked every other time, but this time it did not help and quickly got worse.

I have been dealing with cold sores since I was a baby and that is why I was asking if anyone had a reaction to mangos like a cold sore. Not that I was wondering if I had cold sores. The reaction began like cold sores (itchy and burning, raised, etc.) but became a all over both lips and around the lips. It was slightly raised and crusty. Just like poison ivy. And since I found out that poison ivy and mangos are related I made an educated guess and figured out that it was indeed the mangos.

Secondly I knew I did not have exczema. My husband and 2 of my son's have that. I knew it was a reaction from the mangos when I used the medicine. All I was saying with using it that the medicine might have other uses than just getting rid of exczema. Thought being---Mangos reaction-Poison ivy reaction- exczema being caused by an allergy(all being allergic reactions) that the cream might work on my allergic reation to mangos. And it worked.

I have no cramps, I have no swollen glands, I get cold sores once in a great while when I get a cold and then get the sores, I am very healthy, and know my body well. I just never had an allergic reaction to food before. I am just glad that I figured out that it was a reaction to mangos and that the medicine I tried cleared the complete rash in less than 24 hours.

pinksam what herpes med did you react to?
i reacted to oral valtrex.. what a horrible medicine, the biggest pills ever made in medical history & make you feel absolutely awful. not to mention the puffy face I had on new years from reacting to it!