Yes you could have more than one health variable and you can compare them or do some sort of checksum. Or just periodically save the current health to a backup variable and then compare them. However I will say this seems like a lot of work to prevent a would-be 'cheater'. Is it worth it?
Do you expect a lot of people to cheat in your game? This alpha tester told you they use it and I almost feel that if people go through that many steps to cheat, I would probably let them. It only harms themselves since they are 'breaking' the game.
Paragraph 1: I tried that method but, the Cheat Engine will compare ALL things that has the same value, so, probably the cheater will choose all that have the health value and change it/lock it. I tried saving the health variable to a server but, is client side so, it's cheatable too.
Paragraph 2: I think an medium number of players would cheat. The alpha tester cheated because he told to me that the game is so difficulty and he wanted to know that if is possible to cheat with it. I'm making an Undertale fan-game based synced with the background music. So, like it's a Undertale game, i think that will be a lot of people interested on playing, and, a lot of kid, including the kiddies that think they're anonymous with Cheat Engine. So, they won't handle the difficulty of my game, and, cheat. Like i said, if i could detect the opened programs, it can work too but, if the player tries to rename it to test if he can bypass, he will succed. And, some players won't cheat just to have the fun of the game, that is just survive. And, i don't care about if the player cheats too or not, but, i care about the fun of my game. If the player cheats, what type of fun he will acquire? Like, some games gives you cheat options to make you have fun, but, in my game, that is not possible. Seeing you going trough difficulty phases, dodgin everything, and, having that satisfaction of "I did it!", that's the fun of the game, like an normal rage game.
So, i don't know other types of Ant-cheat method, so, any other better option i would be really thankfull, i think an ant-cheat is not so much needed but, anyways, it will better to have one. Every type of ant-cheat that works, will be useful for me.