The simplest answer to your question would be YES, but you need to take into account what software is listening on that port. Since you've installed LAMP stack (Linux,Apache,MySQL,PHP) then most likely it's Apache 2.4 listening on that port with PHP enabled as well.
You would need to check your Apache (2.4) and PHP (5.5) versions for known vulnerabilities. I would also check if MySQL is exposed as it comes pre-installed as part of LAMP stack.
If you apply updates promptly and follow general best security practices your exposure is similar to many public websites using Apache/MySQL/PHP which I think is quite acceptable.