Congratulations you have won...malware

Hi, yesterday looking for info on dog food I landed on a website that had “congratulations you have won....” I tried to hit back and accidentally clicked closed.... redirected to a different site. Turned phone off to prevent page loading. I have free Mcafree security which detects no threats

1) could I have malware / virus installed on my phone

2) how do I find out / get rid of it

3) what should I do?

thanks