Bumili ng lot ang bf ko na foreigner, sa akin naka pangalan, ngayon gusto nyang ipangalan sa iba?

If the TCT is in your name, ibig kong sabihin ay, your name appears as the registered owner, well, it's yours. You can sell it, you can use it as collateral or a loan, you can donate it you can even pass it on to your heirs. If it is in your name, they will have to prove that there was extrinsic fraud that the title is in your name.
Consult a lawyer and bring all the photocopies of the documents in your possession. Better get a safety deposit box and store your TCT in the safety deposit box para hindi makuha mula sa iyo.