Made my 2nd batch of beer late last night

I bought 2 of 2.5 gl of water from the super market to brew my beer last night. I put 2gl of water on the brewing pot and 3gl remaining on the primary. I know you always lose water while boiling but after 40min boiling I just poured it into the primary where I already had 3 gl of water and made sure the temp was good for the yeast and pitched it and was done for the night. This morning I remembered that I did not check to see how much water I lost while boiling and now I would need to open the lid to check and I don’t know if I can just top it off now if I need to or if its necessary?

Should be ok to add clean water. Just sanitize your hands and anything that touches the wort. You should not have any problems though.

Shine a flashlight from the back side and you can get a good idea of the level. As far as adding more water, do it if you want.