Welcome to our Forum. thanks for your confidence in our service.  I'll do my best to help.  You raise a number of questions. 

1.  What you describe does not sound like lymph nodes.  further, even when you can feel lymph nodes, on some occasions they are normal.  The diagnosis of enlarged lymph nodes is best accomplished by a trained health care provider.

2.  A 4th generation, combination test is more than 99% conclusive at 4 weeks (28 days).  I have never seen a negative 4th generation test become positive after 4 weeks in a person who has not taken anti-HIV therapy.

3. Could this be due to hiv ? Would hiv show weight loss and swollen nodes with 15 to 20 days ?

HIV would not cause weight loss this quickly.  Your symptoms are not likely to be due to HIV.  I recommend you see a clinician to evaluate these symptoms but I would not worry about HIV.

Even if you have swollen lymph nodes. it would be unwise to assume that they represent HIV, particularly with a negative test.  If your lymph nodes were swollen due to HIV, your test would be positive. 

The exposure you describe is a virtually no risk event.  Neither receipt of masturbation (i.e. being fingered) not receipt of rimming is associated with HIV risk. 

I would look for other reasons for your weight loss.  Dizziness on standing could represent dehydration or be part of your weight loss.  It is not suggestive of HIV.

Like masturbation, having someone rub your anus without penetration should not put you at risk for HIV.

My advice is to believe your test results, not worry further about HIV, and work with your doctor to look for other reasons for your weight loss and dizziness.  EWH

Let me start this final reply by stating that the activities you describe are NOT activities that warrant concern about acquisition of HIV (1 or 2) so your questions regarding testing are misdirected.  As for your specific questions:

1.  There is a small amount of HIV-2 seen in India but not much.  This, given your no risk exposures and the rarity of HIV this is not a concern. IN THEORY, if you had been exposed meaningfully to HIV-2, development of antibodies might take longer but the problem is so rare that the data are imprecise.  Certainly well over 90% of HIV-2 infections would be detectable at 4 weeks.

2.  As I said earlier, no penetration, no risk.  This is a "what if" question regarding surface contact without penetration.  It would not put you are risk.  Surface contamination of the sort you describe is typically not a meaningful concern.

3.  You are being paranoid and overthinking this. No have a no risk event and two different tests that are negative.  Believe your test results.

4.  You can reduce your risk for HIV in a number of ways. You can start by asking your partners of their HIV status and when they were last tested- most people tell the truth.  If you are exposed, the most effective means is to take PrEP every day.  Condoms are also highly effective when used throughout he penetrative sexual activity but break about 1% of the time with breakage being higher with new partners and with rectal sex.  Regarding oral sex, there are no proven cases of HIV which have been acquired from receipt of oral sex from an infected person.  Persons performing oral sex 9fellatio) on an infected man are at slight risk for infection.  The U.S. CDC estimates the risk for infection as being about 1 infection for every 10,000 exposure.   

I hope that this information has been helpful.  As per Forum guidelines, this thread will now be closed.  Take care. EWH