Having previously done GHB sodium solution - which is fine to drink straight, although tastes disgusting - I wrongly assumed that GBL is safe to drink straight. I glossed over multiple sources of information on GBL and managed to completely miss the part where it is stated to be caustic.
So after a few days of dosing the GBL - approximately 30ml in total - and assuming it just tasted horrendous, I finally looked up the taste just today. After finding out the relevant information I took a closer look at my mouth and discovered the entire left side of my tongue to be chemically burned off, the back of my throat swollen and my lips also burned. I have no clue how I didn't notice this for 4 days.
Luckily I found out before significant damage was done to my body, though I am left with serious chemical burns throughout my mouth.
Again, I'm not posting this to point the blame on any parties other than myself, but as a safety warning to first time users. I have never been this disappointed in my own sensory skills before - my taste buds were literally being burned off. If you are coming from GHB to GBL you must be aware of the differences.