To me, this sounds like you're taking unnecessary creep damage. The only time you should take creep damage is when you're harassing an enemy, and even then you want to make sure you take less damage then they do! Make sure you're not doing that and actually warrant heals because these items are all pricey if you don't actually need them! Here are the items that can heal you in the game, excluding the Bottle that you're already aware of (and is more often picked up for mana restoration than for healing).
- Tango is a consumable you buy from the main shop with 125 gold. It gives you 4 charges that can be used on a tree to heal you for 115 hp over 16 seconds.
- Healing Slave can be bought for 115 gold from the main shop. If consumed it will heal you for 400 hp over 10 seconds. If you receive damage during this time the effect will be stopped.
/ - Magic Stick and Magic Wand are extremely cost efficient items that gain a charge anytime an enemy casts a spell near you. You can activate the item to restore 15 health and 15 mana per charge. This item is also great for making use of Iron Branches that you should buy at the beginning of almost every game.
- Ring of Regen costs 350 gold and can be bought from the main shop or the side lane shop. It will increase your hp regen by 2.
- Ring of Health increases your hp regen by 5. It costs 875 gold and can be bought from the secret shop or the side lane shop.
- Urn of Shadows costs 875 to make and has an active that will heal an allied hero for 400 hp. The healing is interrupted if the unit takes hero or tower damage.
- Tranquil Boots costs 975 to make will give you 12 hp regen while out of combat. The healing is interrupted for 13 seconds if the hero attacks or is attacked.
- Mekansm is more expensive at 2306 but is a great item for support heroes to make as it heals all allies in a nearby radius for 250 hp instantly. This makes it a great teamfight item and every team should have one.