Nice to meet you in HCM,
Nothing to worry, your chances of contracting HIV
is practically negligible.
First , the chance of an HIV infected person cutting hair in salon before yourself is rarest happening, in that situation too there is no chance of getting infected with HIV through wound after 15 minutes (because the HIV virus wont survive in environment condition more than 30 seconds, maximally ).
As you have sore throat
for 2 days , it is not due to HIV, only the symptoms starts after 4 weeks of minimum period.