What should I do if had been exposed to someone with COVID-19 and have received a SMS message but have received a booster shot?

YOU ARE NOT REQUIRED TO SELF-ISOLATE.

THE SELF-ISOLATION DOES NOT APPLY to the person who has received a COVID-19 vaccine booster shot.
Before terminating your self-isolation, the NPHC has to verify the fact of vaccination with a booster shot, therefore,  please submit the following information at e-mail [email protected] (you are not required to self-isolate while waiting for the response):
•    Name, surname,
•    Personal identity  code,
•    Telephone number at which you have received the SMS message,
•    PLEASE ATTACH a document proving vaccination with a booster shot, e.g. EU digital COVID certificate.  
NOTE. The National Certificate or a paper-card received after vaccination IS NOT ACCEPTED.

It is recommended to take a PCR test no earlier than on the 3rd day after contact (except of recovered individuals who have been diagnosed with a PCR or antigen test less than 90 days previously). You can register through the 1808.lt system by selecting "Vaccinated or recovered persons with high-risk exposure to COVID-19 who are not subject to self-isolation".  You will have to limit the number of people you interact with for 14 days from the last day of exposure. Employed people are only advised to go to work and home if it is not possible to work remotely.

When communicating with other persons, it is recommended to wear personal protective equipment, monitor health status, measure body temperature, maintain physical distance from other persons, ensure proper hand hygiene, cough and sneeze etiquette for at least 14 days from the last day of exposure to someone with COVID-19. If symptoms characteristic of COVID-19 occur, please self-isolate immediately and register for PCR.